Regulating Power Between Power Sources in a Photovoltaic Power System

ABSTRACT

A power system may comprise a plurality of power sources, each connected to a corresponding power regulator. The power regulators may be connected in series or in parallel, and may form a string. Each power regulator may comprise input terminals connected to the corresponding power source, output terminals, and a power converter that may be configured to convert input power from the corresponding power source to output power. The power regulator may further comprise a regulator communications module that may be configured to receive a power regulation indication relating to regulating an operational characteristic of the power regulator. The regulator controller may be configured to instruct the power converter to increase or decrease the regulator operational characteristic based on the power regulation indication, and based on power production characteristics of the power regulator.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.63/297,452, filed on Jan. 7, 2022. The entire disclosure of theforegoing application is incorporated by reference in its entirety.

BACKGROUND

The present disclosure relates generally to photovoltaic power systems.More specifically, aspects of the disclosure provide systems, devices,and methods for regulating power production between power sources in aphotovoltaic power system.

Some power systems may comprise a plurality of power sources. In suchpower systems, the power production of the different power sources mightnot be balanced (e.g., some power sources may produce more power thanothers). Uneven power production may occur in power systems whichproduce more power than may be required by the application (e.g., ahome, a factory) that is connected to the power system (e.g., oversizedsystem or temporary reduction in power requirements). In some instances,a power system may comprise a plurality of parallel connected strings,wherein each string may comprise a plurality of connected power sources.An uneven distribution of power production may result from differencesin the configuration of each string (e.g., a number of power sources ineach string may vary, a length of a wire connecting the strings to acentral module may vary, the different lengths of wire may result indifferent voltage drops across the wires, the differing voltage dropsmay result in different strings producing different voltages, or thelike). In photovoltaic power sources, installation of the photovoltaicpower sources may also result in an uneven distribution of powerproduction.

SUMMARY

The following is a simplified summary of some of inventive concepts forillustrative purposes only. This summary is not an extensive overviewand is not intended to identify key or critical elements of the presentdisclosure. This summary is not intended to limit or constrain thepresent disclosure.

A power system may comprise a plurality of power sources, which may beconfigured to generate power. A power system may further comprise astring, which may comprise a plurality of power regulators connected inseries or in parallel. Each power regulator may comprise inputterminals, output terminals, a power converter, a regulatorcommunications module, and a regulator controller. The input terminalsmay be connected to a corresponding power source. The power convertermay be configured to convert input power, from the corresponding powersource, to output power. The regulator communications module may beconfigured to receive at least one regulation signal. The regulationsignal may indicate the regulation of an operational characteristic of apower regulator. The regulation signal may be a broadcast signal or amulticast signal. The regulator controller may be connected to the powerconverter and the regulator communications module. The regulatorcontroller may control the power converter. In particular, the regulatorcontroller may increase or decrease the operational characteristic ofthe power regulator based on the power regulation indication and furtherbased on power production characteristics of the power regulator. Thepower converter may adjust the power output of a power regulator toremedy uneven distribution of power throughout the power system. Thepower regulation indication may be at least one of a required regulatoroutput, an increase indication, or a decrease indication.

A method may comprise regulating power produced by a plurality of powersources in an array of power sources. The array of power sources maycomprise a plurality of strings connected in parallel, where each stringmay comprise a plurality of power regulators connected in series or inparallel. Each power source in the array of power source may beconnected to a corresponding power regulator. The method may comprisethe steps of determining a power regulation indication for regulatingoutput power of the plurality power regulators in the array of powersources and transmitting a regulation signal as a broadcast signal or amulticast signal to at least some of the power regulators in the arrayof power sources. The regulation signal may correspond to the powerregulation indication. The method may further include the step ofincreasing, decreasing or maintaining at least one output characteristicof each power regulator for each power regulator that received theregulation signal. The increasing, decreasing or maintaining of at leastone output characteristic may be based on the received regulationsignal, and based on power production characteristics of the powerregulator. The power regulation indication may be at least one of:required regulator output, an increase indication, or a decreaseindication.

A system may comprise a power regulator in a plurality (e.g., array) ofpower sources, which may comprise input terminals, output terminals, apower converter, a regulator communications module and a regulatorcontroller. The input terminals may be configured to be connected to acorresponding power source of the plurality of power sources. The powerconverter may be configured to convert input power from thecorresponding power source to output power. The regulator communicationsmodule, may be configured to receive at least one regulation signal. Theregulation signal may correspond to a power regulation indication. Thepower regulation indication may relate to regulating an operationalcharacteristic of the power regulator. The regulation signal may be oneof a broadcast signal or a multicast signal. The regulator controllermay be connected to the power converter and the regulator communicationsmodule. The regulator controller may be configured to control the powerconverter to either increase or decrease the regulator operationalcharacteristic of the power regulator based on the power regulationindication, and based on power production characteristics of the powerregulator. The power regulation indication may be at least one of:required regulator output, an increase indication, or a decreaseindication.

An array of power sources may comprise a plurality of strings and aplurality of power regulators. Each string, of the plurality of strings,may comprise power sources, of the plurality of power sources. Eachpower regulator within the plurality of power regulators may compriseinput terminals, output terminals, a power converter, a regulatorcommunications module, and a regulator controller. The input terminalsmay be configured to connect to a corresponding power source of theplurality of power sources. The power converter may be configured toconvert input power from the corresponding power source to output power.The regulator communications module, may be configured to receive atleast one regulation signal. The regulation signal may correspond to apower regulation indication. The power regulation indication may relateto regulating an operational characteristic of the power regulator. Theregulation signal may be one of a broadcast signal or a multicastsignal. The regulator controller may be connected to the power converterand the regulator communications module. The regulator controller may beconfigured to control the power converter to either increase or decreasethe regulator operational characteristic of the power regulator based onthe power regulation indication, and based on a power productioncharacteristic of the power regulator. The power regulation indicationmay be at least one of: required regulator output, an increaseindication, or a decrease indication.

The power regulator may store a characteristic curve defining acorrespondence between regulator operational characteristics of thepower regulator. The characteristic curve may comprise a droop over anoperating range of the power regulator. The regulator controller maycontrol the power converter to increase, decrease, or maintain theregulator operational characteristic at least based on thecharacteristics curve.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure is illustrated by way of example and is notlimited in the accompanying figures in which like reference numeralsindicate similar elements and in which:

FIGS. 1A and 1B illustrate example photovoltaic power systems in whichpower harvesting may be regulated, in accordance with aspects of thedisclosure herein.

FIG. 1C illustrates example components of a power regulator with whichpower harvesting may be regulated, in accordance with aspects of thedisclosure herein.

FIG. 2 illustrates an example method for regulating power and regulatingpower harvesting in an array of power sources, in accordance withaspects of the disclosure herein.

FIGS. 3A-3E illustrate example graphical representations of powerregulation in an array of power sources, in accordance with aspects ofthe disclosure herein.

FIGS. 4A-4D illustrate example graphical representations of powerregulation in an array of power sources, in accordance with aspects ofthe disclosure herein.

FIG. 5 illustrates an example method for power regulation in an array ofpower sources, in accordance with aspects of the disclosure herein.

FIGS. 6A and 6B illustrate example graphical representations of changesin power production versus changes in regulator operationalcharacteristics, in accordance with aspects of the disclosure herein.

FIG. 6C illustrates an example method for regulating power production inan array of power sources based on determined and actual operationalcharacteristics of a photovoltaic power system, in accordance withaspects of the disclosure herein.

FIGS. 7A and 7B illustrate examples of regulator characteristic curvesof two power regulators connected in series, in accordance with aspectsof the disclosure herein.

FIGS. 8A and 8B illustrate examples of regulator characteristic curvesof two power regulators connected in parallel, in accordance withaspects of the disclosure herein.

FIGS. 9A-9E illustrate examples of various characteristic curves whichmay be used to reduce differences between operational characteristics ofpower regulators in an array of power regulators, in accordance withaspects of the disclosure herein.

FIG. 10 illustrates an example of a photovoltaic power system in whichpower regulators in a string may be short circuited, in accordance withaspects of the disclosure herein.

FIG. 11 illustrates an example of an output current versus outputvoltage characteristic curve of a power regulator, in accordance withaspects of the disclosure herein.

FIG. 12 illustrates an example in which a central module is implementedas an inverter, in accordance with aspects of the disclosure herein.

FIG. 13 illustrates an example in which a central module is implanted asa combiner, in accordance with aspects of the disclosure herein.

FIG. 14 illustrates an example of a power regulator which comprises aDC-DC converter, in accordance with aspects of the disclosure herein.

FIG. 15 illustrates an example of a power regulator which comprises aDC-AC converter, in accordance with aspects of the disclosure herein.

DETAILED DESCRIPTION

In the following description of the various embodiments, reference ismade to the accompanying drawings, which form a part hereof, and inwhich are shown, by way of illustration, various embodiments in whichaspects of the discloser may be practiced. It is to be understood thatother embodiments may be utilized, and structural and functionalmodifications may be made without departing from the scope of thepresent disclosure.

The present disclosure includes devices, systems, and methods forregulating power production in an array of power sources. According tofeatures of the disclosure herein, a central module (e.g., an inverter)may determine a power regulation indication that may be used to regulatepower between power sources. Regulating the power between the powersources may comprise regulating output power from power regulators inthe array of power sources. The power regulation indication may specifyan output characteristic of a power regulator connected to each powersource. The power regulation indication may be an increase indication,which may instruct the power regulator to increase the operationalcharacteristic of the power regulator. Additionally or alternatively,the power regulation indication may be a decrease indication, which mayinstruct the power regulator to decrease the operational characteristicof the power regulator. The central module may transmit the powerregulation indication to the power regulators in the array of powersources. Power regulation according to the present disclosure may alsoemploy droop curve techniques to reduce a difference between theoperational characteristics of the power regulators.

Reference is now made to FIGS. 1A and 1B, which are exampleillustrations of a power system 100, in which power harvesting may beregulated in accordance with aspects of the disclosure herein. Powersystem 100 may comprise a plurality of power sources (e.g., powersources 108), a plurality of power regulators (e.g., power regulators110, which may be abbreviated as “REG” in FIGS. 1A and 1B), and acentral module (e.g., central module 101). Each power source 108 (e.g.,108-11, . . . , 108-1M, 108-21, . . . , 108-2M, 108-N1, . . . , 108-NM)may be connected to an input terminal of a corresponding power regulator110 (e.g., 110-11, . . . , 110-1M, 110-21, . . . , 110-2M, 110-N1, . . ., 110-NM). The plurality of power sources 108 and corresponding powerregulators 110 may be arranged in an array of power sources (e.g., arrayof power sources 102). Array of power sources 102 may comprise one ormore strings (e.g., strings 106-1, 106-2, . . . , 106-N).

String 106 may comprise a group of serially connected power regulators110. As illustrated in FIG. 1A, string 106-1 may comprise a group ofserially connected power regulators 110-11, 110-12, 110-13, . . . ,110-1M. As illustrated in FIG. 1A, string 106-2 may comprise a group ofserially connected power regulators 110-21, 110-22, 110-23, . . . ,110-2M. As further illustrated in FIG. 1A, string 106-N may comprise agroup of serially connected power regulators 110-N1, 110-N2, 110-N3, . .. , 110-NM.

String 106 may comprise a group of parallel connected power regulators110. As illustrated in FIG. 1B, string 106-1 may comprise a group ofparallel connected power regulators 110-11, 110-12, 110-13, . . . ,110-1M. As illustrated in FIG. 1B, string 106-2 may comprise a group ofparallel connected power regulators 110-21, 110-22, 110-23, . . . ,110-2M. As further illustrated in FIG. 1B, string 106-N may comprise agroup of parallel connected power regulators 110-N1, 110-N2, 110-N3, . .. , 110-NM. In FIGS. 1A and 1B, strings 106-1, 106-2, . . . , 106-N maybe connected in parallel by connecting output terminals 111-11, 111-21,. . . , 111-N1 of strings 106-1, 106-2, . . . , 106-N, respectively, toinput terminal 113-1 of central module 101, and by connecting outputterminals 111-12, 111-22 and 111-N2 of strings 106-1, 106-2, . . . ,106-N, respectively, to input terminal 113-2 of central module 101(e.g., an inverter or a combiner).

Central module 101 may comprise a central controller 112, a centralcommunication module 114, sensor(s) 116, and input terminals 113-1 and113-2. Central controller 112 may be connected to central communicationmodule 114. Central controller 112 may be connected to sensor(s) 116.Array of power sources 102 may be connected to central module 101 byconnecting output terminals 111 of strings 106 with input terminals 113of central module 101. For example, input terminal 113-1 may beconnected to output terminals 111-11, 111-21, . . . , 111-N1 of strings106-1, 106-2, . . . , 106-N respectively. Input terminal 113-2 may beconnected to output terminals 111-12, 111-22, . . . , 111-N2 of strings106-1, 106-2, . . . , 106-N respectively. Central module 101 may beembodied in an inverter described below in conjunction with FIG. 12 , ora combiner as described below in conjunction with FIG. 13 . Sensors(s)116 may be one or more voltage sensors, one or more current sensors, oneor more temperature sensors configured to measure variouscharacteristics of central module 101.

Referring to FIG. 1C, each power regulator 110 may comprise regulatorcontroller 120, power converter 122, regulator communications module124, and sensors(s) 126. As illustrated in FIG. 1C, regulator controller120 may be connected to power converter 122, regulator communicationsmodule 124, and sensor(s) 126. Power converter 122 may comprise powerinput terminals 130-1 and 130-2, and power output terminals 132-1 and132-2. Power converter 122 may be a DC to DC (DC-DC) converter, a DC toAC (DC-AC) converter, an AC to AC (AC-AC) converter, or an AC to DC(AC-DC) converter. Output terminals 128-1 and 128-2 of power source 108may be connected to power input terminals 130-1 and 130-2 of powerconverter 122, respectively. Power converter 122 may be configured toreceive power from power source 108 at input terminals 130-1 and 130-2of power converter 122 and to provide power at output terminals 132-1and 132-2 of power converter 122. Sensors(s) 126 may be one or more ofvoltage sensors, current sensors, or temperature sensors configured tomeasure various characteristics of power regulator 110. FIG. 13 belowrelates to an example implementation of power regulator 110 whichcomprises a DC-DC converter. FIG. 14 below relates to an exampleimplementation of power regulator 110 which comprises a DC-AC converter.

Each power source of the plurality of power sources 108 may beconfigured to generate electrical power at the output terminals (e.g.,output terminals 128-1 and 128-2 of power source 108). Power source 108may comprise a direct current (DC) power source, such as a photovoltaicmodule, a battery (e.g., a lithium ion battery, lead-acid batteries,solid-state batteries, a redox flow battery, or the like), a capacitor,or a fuel cell. Additionally or alternatively, power source 108 maycomprise an alternating current (AC) power source, such as a windturbine, a flywheel, or a fuel powered generator configured to generateAC power at the output terminal of power source 108. Power regulator 110may receive and regulate power from power source 108. Power productionbetween power regulators 110 in array of power sources 102 might not beevenly distributed between power sources 108. As mentioned above, theuneven distribution of power production may result in an increase intemperature (e.g., overheating) of some power regulators 110. Theincrease in temperature may result in an increase in losses and mayincrease the probability of regulator failure and damage (e.g., reducethe Mean Time Between Failures—MTBF), or may even result in fire. Theuneven power production between power regulators 110 may result inunder-utilization of the power available from power source 108. Theuneven power production between power regulators 110 may result fromvariations in regulator operational characteristics of power regulator110 (e.g., output voltage, output current, output power, operatingtemperature, power converter duty cycle, or any combination thereof).

To regulate the power harvesting between power regulators 110 in arrayof power sources 102, central controller 112 (e.g., an inverter) may beconfigured to determine a power regulation indication. The powerregulation indication may be based on a comparison of one or moredetermined operational characteristics of power system 100 and one ormore actual (e.g., measured) operational characteristics of power system100. A determined operational characteristic may be one that is adesigned, preprogrammed, predetermined, or calculated based arequirement of the system or based on measured parameters in the system.In some embodiments, the power regulation indication may be based on acomparison of the determined output power and the actual (e.g.,measured) output power from power system 100. In some embodiments, thepower regulation indication may be based on a comparison of thedetermined output voltage and the actual (e.g., measured) output voltagefrom power system 100. In some embodiments, the power regulationindication may be based on a comparison of the determined output currentand the actual (e.g., measured) output current from power system 100. Inexamples where central module 101 is an inverter (e.g., inverter 1100illustrated in FIG. 11 ), the determined and actual (e.g., measured)operational characteristics of power system 100 may relate to one ormore determined and actual (e.g., measured) operational characteristicsof inverter 1100 (e.g., determined inverter input power compared toactual (e.g., measured) inverter input power, determined inverter inputvoltage compared to actual (e.g., measured) inverter input voltage, ordetermined inverter input current compared to actual (e.g., measured)inverter input current, or any combination thereof). The term “comparedto” herein may relate to either a difference or a ratio between thedetermined and the actual (e.g., measured) operational characteristics.The determined operational characteristics may depend on actualimplementation of central module 101. The determined operationalcharacteristics of power system 100 (e.g., determined inverter inputpower, determined inverter input current, determined inverter inputvoltage) may be based on a determined (e.g., required, specified,measured, maximum) level (e.g., of power, current, voltage) that powersystem 100 may be configured to produce for use by the application. Inthe case of more than one determined operational characteristic of powersystem 100 being employed (e.g., a combination of determined operationalcharacteristics), the values of the different determined operationalcharacteristics (e.g., voltage, current, power) may be normalized, and asum of differences may be employed to combine the different determinedoperational characteristics (e.g., using an average or a weightedaverage of the values of the different determined operationalcharacteristics).

The power regulation indication may relate to a regulator operationalcharacteristic of power regulators 110 in array of power sources 102. Asdiscussed in connection with FIGS. 3A to 3E, 4A to 4D, and 5 the powerregulation indication may be an expected regulator output. A powerregulation indication may be a change indication (e.g., an increaseindication or a decrease indication) or a no-change indication, asillustrated in FIGS. 6A-6C. In some examples, the power regulationindication may relate to all power regulators 110, and centralcommunications module 114 may broadcast a signal corresponding to thepower regulation indication to all power regulators 110 in array ofpower sources 102. In some examples, the power regulation indication mayrelate to some of power regulators 110 (e.g., a group of powerregulators 110 across one or more of strings 106-1, 106-2, . . . ,106-N), and central communications module 114 may transmit a multicastsignal to the group of power regulators 110. In some examples, the powerregulation indication may relate to one specific power regulator 110,and central communications module 114 may transmit a unicast signal tothe one specific power regulator 110. The term “regulation signal” mayrelate to a signal corresponding to the power regulation indicationtransmitted from central module 101 to at least one power regulator 110.

Regulator communications module 124, in each one of power regulators110, may be configured to receive a regulation signal. Based on thereceived regulation signal, and on at least one power productioncharacteristic of power regulator 110, regulator controller 120 maycontrol (e.g., instruct, provide a command, etc.) power converter 122 toincrease, decrease, or maintain one or more of the regulator operationalcharacteristics of power regulator 110. The regulator operationalcharacteristics of power regulator 110 may be regulator output voltage,regulator output current, regulator output power, regulator operatingtemperature (e.g., case temperature, component or componentstemperature, ambient temperature within a regulator casing, and thelike), power converter duty cycle, or any combination thereof. Asfurther elaborated below, a power production characteristic of powerregulator 110 may be a maximum power point (MPP) of a correspondingpower source 108, maximum operating temperature, output increasefunction, or output decrease function. The power productioncharacteristic of power regulator 110 may be a current versus voltagecurve of power regulator 110 or a power versus voltage curve of powerregulator 110, or any combination of the above mentioned powerproduction characteristics.

Central communications module 114 of central module 101 may beconfigured to transmit signals to power regulators 110. Regulatorcommunications module 124, of each one of power regulators 110, may beconfigured to receive signals from central module 101. Centralcommunications module 114 may be further configured to receive signalsfrom power regulators 110, and each one of regulator communicationsmodules 124 may be further configured to transmit signals to centralmodule 101. As such, regulator communications module 124 of powerregulator 110 and central communications module 114 of central module101 may be configured to communicate based on a transmission protocoldefining the transmission frequency or frequencies, a modulation scheme(e.g., Amplitude shift keying—ASK, Frequency shift keying—FSK,Quadrature Phase Shift Keying—QPSK, Quadrature AmplitudeModulation—QAM), multiple access scheme (e.g., Time Division MultipleAccess—TDMA, Frequency Division Multiple Access—FDMA, Code DivisionMultiple Access—CDMA, Carrier Sense Multiple Access—CSMA, Aloha),encoding/decoding schemes (e.g., Non Return to Zero—NRZ, Manchestercoding, Block coding), or the like. The transmitted and received signalsbetween central module 101 and power regulator 110 may containinformation relating to the power production in power system 100.

Following the increase, decrease, or maintenance of the regulatoroperational characteristics of some or all of power regulators 110 basedon the received power regulation indication, the power productionbetween power regulators 110 in array of power sources 102 may besubstantially balanced. The terms “balance of power production” or“distribution of power production” may describe differences in theregulator operational characteristics between power regulators 110(e.g., power regulators within one of strings 106-1, 106-2, . . . ,106-N, or in array of power sources 102). The terms “balance of powerproduction” and “distribution of power production” may describe aweighted distribution of power production, where power regulators 110with higher MPPs may produce more power than power regulators 110 withlower MPPs (e.g., the distribution of power production may be fair). Theterms “balance of power production” and “distribution of powerproduction” may describe a weighted distribution of power production,where power regulators 110 with longer lifetimes may produce less powerthan power regulators 110 with shorter lifetimes. The term “lifetime”may be considered as equivalent to the “age” of the power regulator. Inbalanced power production, the differences in the regulator operationalcharacteristics or operating temperature may be smaller than inunbalanced power production. Balanced power production may relate to(e.g., refer to) the standard deviation of the regulator operationalcharacteristics of power regulators 110. In balanced (e.g., evenlydistributed) power production, the standard deviation of the regulatoroperational characteristics of power regulators 110 may be smaller thanin unbalanced (e.g., uneven) power production. Balanced power productionmay relate to (e.g., refer to) an average of differences between thetotality of power regulators 110 and a selected reference powerregulator 110 (e.g., a reference power regulator 110 selected from oneof strings 106 or from array of power sources 102). In balanced (e.g.,evenly distributed) power production, the average of the differencesbetween the totality of power regulators 110 and the selected referencepower regulator 110 may be smaller than in unbalanced power production.The terms “balance of power production” and “distribution of powerproduction” may describe the level of the regulator operationalcharacteristics of one or more of power regulators 110. The regulatoroperational characteristics of all power regulators 110 may be within aspecified range of values. In unbalanced power production, the regulatoroperational characteristics of one or more of power regulators 110 mightnot be within the specified range of values. As mentioned above, underconditions of unbalanced power production between power regulators 110,the probability of damage to power regulators 110 or power sources 108may increase relative to the conditions of balanced power productionbetween power regulators 110.

Reference is now made to FIG. 2 , which illustrates an example methodfor regulating power harvesting in an array of power sources. In step200, a power regulation signal for regulating output power between powerregulators 110 in array of power sources 102 may be determined for arrayof power sources 102. The power regulation signal may correspond to apower regulation indication (e.g., required output power, requiredoperation temperature, power increase indication, power decreaseindication, and the like as further elaborated herein). As mentionedabove and as further described below, the power regulation indicationmay be an expected regulator output, an increase indication, a decreaseindication, a no-change indication, or any combination thereof. Thepower regulation indication may relate to the regulator operationalcharacteristic (e.g., regulator output voltage, regulator outputcurrent, regulator output power, regulator operating temperature, dutycycle of the DC-DC converter), or the like. With reference to FIGS. 1Aand 1C, a power regulation indication may be determined for powerregulators 110 in array of power sources 102 by central module 101. Thepower regulation indication may relate to all power regulators 110, orto one or more of strings 106. The power regulation indication may bedetermined by central controller 112 based on the determined operationalcharacteristics of power system 100.

In step 202, the power regulation signal corresponding to the powerregulation indication may be transmitted to at least some of powerregulators 110 in array of power sources 102. The power regulationindication may be common to all power regulators 110, and the signal maybe broadcast to all power regulators 110 in array of power sources 102.The regulation indication may be transmitted only to some of powerregulators 110 as a multicast signal. The regulation indication may betransmitted to one power regulator 110 as a unicast signal. Withreference to FIGS. 1A and 1C, central communications module 114 maytransmit the regulation signal to power regulators 110 in array of powersources 102. Central communications module 114 may transmit theregulation indication as a multicast signal to only some of powerregulators 110 in array of power source 102 (e.g., to power regulators110-21, 110-22, 110-23, . . . , 110-2M in string 106-2). Centralcommunications module 114 may transmit the regulation indication asunicast signal to one of power regulators 110.

In step 204, the power regulation signal may be received by at least onepower regulator 110 of power source 108 in array of power sources 102.With reference to FIG. 1C, regulator communications module 124 in powerregulator 110 may receive the regulation signal relating to the powerregulation indication.

In step 206, for each power regulator 110 that received the powerregulation signal, at least one of the regulator operationalcharacteristics may be increased, decreased, or maintained based on thereceived regulation signal and the power production characteristics ofpower regulator 110. With reference to FIG. 1C, regulator controller 120may control (e.g., instruct, provide a command, etc.) power converter122 to increase, decrease, or maintain the regulator operationalcharacteristic (e.g., output voltage, output current, output power,operating temperature, converter duty cycle, or any combination thereof)of power regulator 110 based on a regulation signal received byregulator communications module 124.

Following are examples relating to power regulation between powerregulators 110 in array of power sources 102, or in one of strings 106,according to various aspects of the present disclosure.

As mentioned above, one example of a power regulation indication may bean expected regulator output. The expected regulator output may relateto a value of one or more regulator operational characteristics of powerregulators 110 (e.g., regulator output voltage, regulator outputcurrent, regulator output power, regulator operating temperature, dutycycle of the power converter, or the like). Reference is now made toFIGS. 3A, 3B, 3C, 3D, and 3E, which illustrate examples of powerregulation in an array of power sources (e.g., array of power sources102 as depicted in FIGS. 1A and 1B) where the power regulationindication may be an expected regulator output. As illustrated in FIGS.3A-3E, array of power sources 102 may comprise nine power sources 108(e.g., three strings of three power sources), wherein each power source108 may be connected to a respective power regulator 110. FIGS. 3A-3Edepict column diagrams of power, where each column represents the powerof power regulator 110. The horizontally hatched section of a columnrepresents produced power. The cross hatched section of a columnrepresents potential power which is not produced by power regulator 110.As illustrated in FIGS. 3A-3E, the determined operational characteristicof central module 101 (e.g., determined inverter input power requiredfor a load) may be 4000 Watts (4000 W) of power (e.g., array of powersources 102 may produce 4000 W of power since 4000 W of power is thedemand from the application). FIG. 3A depicts an example of a state ofpower system 100 at time T1. At time T1, the determined inverter inputpower may be 4000 W of power, all power regulators 110 may operate atthe MPP, and central controller 112 may determine an expected regulatoroutput of 1000 W expected from each power regulator 110. Centralcommunications module 114 may transmit a regulation signal relating to(e.g., indicating) the expected regulator output to power regulators 110(e.g., to all power regulators as a broadcast signal). Each powerregulator 110 may receive the regulation signal which indicates theexpected regulator output, and may compare the actual (e.g., measured)regulator output to the received expected regulator output. Based onthis comparison and the MPP associated with each power regulator 110,each power regulator 110 may increase, decrease, or maintain theregulator output (e.g., each power regulator 110 may output the minimumamount of power between the received expected regulator output, and theMPP associated with power regulator 110). In FIG. 3A (e.g., at time T1),central module 101 may receive only 3000 W of power (e.g., the actualinverter input power may be 3000 W of power).

FIG. 3B depicts an example of a state of power system 100 at time T2. Attime T2, the determined inverter input power may still be 4000 W ofpower and all power regulators 110 may operate at the MPP. In FIG. 3B,the MPP of REG 2 may increase to 500 W, the MPP of REG 4 may increase to700 W, and the MPP of REG 8 may increase to 900 W. In FIG. 3B (e.g., attime T2), central module 101 may receive 4000 W of power (e.g., theactual inverter input power may be 4000 W of power). Central controller112 may still determine an expected regulator output of 1000 W expectedfrom each power regulator 110. Central communications module 114 maytransmit a regulation signal relating to (e.g., indicating) the expectedregulator output to power regulators 110. Each power regulator 110 mayreceive the regulation signal and may compare the actual (e.g.,measured) regulator output to the received expected regulator output.Based on this comparison and the MPP associated with each powerregulator 110, each power regulator 110 may increase, decrease, ormaintain the regulator output.

FIG. 3C depicts an example of a state of power system 100 at time T3. Attime T3, the determined inverter input power may still be 4000 W ofpower. In FIG. 3C, the MPP of REG 8 may increase to 1000 W. If centralmodule 101 does not adjust the expected regulator output of the powerregulators 110 at time T3 from 1000 W, the input power to central module101 may be 4100 W. As such, central controller 112 may determine anexpected regulator output of 900 W from each power regulator 110.Central communications module 114 may transmit a regulation signalrelating to (e.g., indicating) the expected regulator output to powerregulators 110. Each power regulator 110 may receive the regulationsignal which may indicate the expected regulator output, and may comparethe actual (e.g., measured) regulator output to the received expectedregulator output. Based on this comparison and the MPP associated witheach power regulator 110, each power regulator 110 may increase,decrease, or maintain its regulator output. As illustrated in FIG. 3C,REG 8 may reduce the output power from 1000 W to 900 W. The crossedhatched area in the column associated with REG 8 may indicate the excesspower which REG 8 might not produce.

FIG. 3D depicts an example of a state of power system 100 at time T4. Attime T4, the determined inverter input power may still be 4000 W ofpower. In FIG. 3D (e.g., at time T4), the MPP of REG 1 may increase to500 W and the MPP of REG 3 may increase to 900 W. If central module 101does not adjust the expected regulator output, the input power tocentral module 101 may be 4900 W. As such, central controller 112 maydetermine an expected regulator output of 556.66 W from each powerregulator 110. Central communications module 114 may transmit aregulation signal relating to (e.g., indicating) the expected regulatoroutput to power regulators 110. Each power regulator 110 may receive theregulation signal which may indicate the expected regulator output, andmay compare the actual (e.g., measured) regulator output to the receivedexpected regulator output. Based on this comparison and the MPPassociated with each power regulator 110, each power regulator 110 mayincrease, decrease, or maintain the regulator output. As illustrated inFIG. 3D, REG 4, and REG 8 may reduce the regulator output to 556.66 W.REG 3 may increase the regulator output to 566.66 W.

FIG. 3E depicts an example of a state of power system 100 at time T5. Attime T5, the determined inverter input power may still be 4000 W ofpower. In FIG. 3E (e.g., at time T5), the MPP of REG 5 and REG 6 mayincrease to 600 W, the MPP of REG 7 may increase to 800 W, and the MPPof REG 9 may increase to 900 W. If central module 101 does not adjustthe expected regulator output from the 556.66 W at time T4, then thetotal input power to central module 101 may be 6500 W. As such, centralcontroller 112 may determine an expected regulator output of 444.44 Wfrom each power regulator 110. Central communications module 114 maytransmit a regulation signal relating to (e.g., indicating) the expectedregulator output to power regulators 110. Each power regulator 110 mayreceive the regulation signal which may indicate the expected regulatoroutput, and may compare the actual (e.g., measured) regulator output tothe received expected regulator output. Based on this comparison and theMPP associated with each power regulator 110, each power regulator 110may increase, decrease, or maintain the regulator output. As illustratedin FIG. 3E, REG 1, REG 2, REG 3, REG 4, and REG 8 may reduce the outputpower to 444.44 W. REG 5, REG 6, REG 7, and REG 9 may increase theoutput power to 444.44 W.

Reference is now made to FIGS. 4A, 4B, 4C, and 4D, which illustratepower regulation in array of power sources 102 (e.g., as depicted inFIGS. 1A and 1B) where the power regulation indication may be anexpected regulator output. As illustrated in FIGS. 4A-4D, array of powersources 102 may comprise nine power sources 108 (e.g., three strings ofthree power sources), each connected to a respective power regulator110. FIGS. 4A-4D depict column diagrams of power, where each columnrepresents the power associated with each power regulator. Horizontallyhatched sections of a column represent produced power. Cross hatchedsections of a column represent potential power that might not beproduced by a regulator. FIG. 4A depicts an example of a state of powersystem 100 at time T6. At time T6, the determined inverter input powermay be 4000 W of power, all power regulators 110 may operate at the MPP,and central controller 112 may determine an expected regulator output of900 W from each power regulator 110. Central communications module 114may transmit a regulation signal relating to (e.g., indicating) theexpected regulator output to power regulators 110 (e.g., to all powerregulators as a broadcast signal). Each power regulator 110 may receivethe regulation signal which may indicate the expected regulator output,and may compare the actual (e.g., measured) regulator output to thereceived expected regulator output. Based on this comparison and the MPPassociated with each power regulator 110, each power regulator 110 mayincrease, decrease, or maintain the regulator output (e.g., each powerregulator outputs the minimum between the received expected regulatoroutput and the MPP associated with the power regulator).

FIG. 4B depicts an example of a state of power system 100 at time T7. Attime T7, the MPP and the output power of REG 1 may increase to 200 W. Attime T7, central module 101 may reduce the determined inverter inputpower to 3600 W. Central controller 112 may determine an expectedregulator output of 400 W from each power regulator 110 (e.g., wherecentral module 101 may have information relating to the number ofregulators in array of power sources 102). Central communications module114 may transmit a regulation signal relating to (e.g., indicating) theexpected regulator output to power regulators 110. Each power regulator110 may receive the regulation signal which may indicate the expectedregulator output, and may compare the actual (e.g., measured) regulatoroutput to the received expected regulator output. Based on thiscomparison and the MPP associated with each power regulator 110, eachpower regulator 110 may increase, decrease, or maintain the powerregulator output. As illustrated in FIG. 4B, REG 1 may increase theoutput power to 200 W (e.g., the MPP). REG 3, REG 4, REG 7, and REG 8may each reduce the output power to 400 W. However, central module 101may still receive only 3000 W at the input (e.g., the actual inverterinput power may be 3000 W of power).

FIG. 4C depicts an example of a state of power system 100 at time T8. Attime T8, the determined inverter input power may still be 3600 W ofpower. In FIG. 4C, the MPP of REG 5 may increase to 400 W and REG 5 mayincrease the output power to 400 W. If central module 101 does notadjust the expected regulator output at time T8 from 400 W, then theinput power to central module 101 may be 3200 W. As such, centralcontroller 112 may determine an expected regulator output of 500 W fromeach power regulator 110. Central communications module 114 may transmita regulation signal relating to (e.g., indicating) the expectedregulator output to power regulators 110. Each power regulator 110 mayreceive the regulation signal which may indicate the expected regulatoroutput, and may compare the actual (e.g., measured) regulator outputcharacteristic to the received expected regulator output. Based on thiscomparison and the MPP associated with each power regulator 110, eachpower regulator 110 may increase, decrease, or maintain the powerregulator output. As illustrated in FIG. 4C, REG 5 may increase theoutput power to 400 W. REG 3, REG 4, REG 7, and REG 8 may each increasethe output power to 500 W, and central module 101 may receive 3600 W atthe input (e.g., the actual inverter input power may be 3000 W ofpower).

FIG. 4D depicts an example of a state of power system 100 at time T9. Attime T9, the determined inverter input power may still be 3600 W ofpower. In FIG. 4D (e.g., at time T9), the MPP of REG 1 and REG 2 mayincrease to 500 W. If central module 101 does not adjust the expectedregulator output from the 500 W at time T9, then the input power tocentral module 101 may be 4200 W. As such, central controller 112 maydetermine an expected regulator output of 400 W from each powerregulator 110. Central communications module 114 may transmit aregulation signal relating to (e.g., indicating) the expected regulatoroutput to power regulators 110. Each power regulator 110 may receive theregulation signal which may indicate the expected regulator output, andmay compare the actual (e.g., measured) regulator output to the receivedexpected regulator output. Based on this comparison and the MPPassociated with each power regulator 110, each power regulator 110 mayincrease, decrease, or maintain the regulator output. As illustrated inFIG. 4D, REG 1 and REG 2 may each decrease the output to 400 W. Asfurther illustrated in FIG. 4D, REG 3, REG 4, REG 7, and REG 8 may eachdecrease the output power to 400 W, and central module 101 may receive3600 W at the input (e.g., the actual inverter input power may be 3600 Wof power).

In the examples described above in conjunction with FIGS. 3A-3E and4A-4D, central module 101 may iteratively set the expected regulatoroutput until the determined inverter input power and the actual (e.g.,measured) inverter input power match. To do so, central module 101 mayimplement a search algorithm (e.g., linear search, binary search). Forexample, referring to FIGS. 3B and 3C, central controller 112 mayiteratively reduce the expected regulator output from 1000 W to 900 W.With reference to FIGS. 4B and 4C, central controller 112 mayiteratively increase the expected regulator output from 400 W to 500 W.

The examples described in conjunction with FIGS. 3A to 3E, and 4A to 4Dmay describe power regulators connected in a series string. In a seriesstring, the current may be the same for all power regulators. As such,the expected regulator output may relate to the regulator outputvoltage. Balancing power production may relate to balancing powerproduction between strings 106. Balancing power production betweenstrings 106 may relate to balancing the currents produced by strings106. As such, the expected regulator output may relate to the outputcurrent of the power regulators in the string.

The description above described the use of expected regulator outputs,wherein an expected regulator output may relate to output power of powerregulators 110. As mentioned above, the expected regulator output maycorrespond to output voltage, output current, operating temperature,duty cycle, or output frequency (e.g., if the power regulator includes aDC-AC converter as shown in FIG. 14 ) of power regulators 110, or to anycombination thereof. When the expected regulator output is the voltageof power regulator 110, the expected regulator output may be determinedbased on the voltage determined by central module 101 (e.g., the voltagethat the application may demand) and the number of power regulators 110in string 106. When the expected regulator output of power regulator 110is current, the expected regulator output may be determined based on thecurrent determined by central module 101 (e.g., the current that theapplication may demand) and the number of strings 106. Thus, centralcontroller 112 may determine the expected regulator output of powerregulators 110 based on the determined operational characteristics ofpower system 100 and further based on a regulation number (e.g., thenumber of power regulators 110 in array of power sources 102, the numberof power regulators 110 in a string 106, the number of strings 106 inarray of power sources 102).

Reference is now made to FIG. 5 . FIG. 5 depicts a method for regulatingpower in an array of power sources (e.g., array of power sources 102)based on expected regulator output. The method in FIG. 5 relates toemploying an expected regulator output for regulating the power in arrayof power sources 102, as described above in conjunction with FIGS. 3A-3Eand 4A-4D. In step 500, a determined operational characteristic of apower system may be identified. The determined operationalcharacteristic of a power system may be pre-defined or may be defined bya determined output power, output voltage, or output current (e.g., ofan array of power sources, or of a central module such as an inverter ora combiner). With reference to FIG. 1A or 1B, central controller 112 ofcentral module 101 may identify a determined operational characteristic(e.g., of array of power sources 102).

In step 502, an actual (e.g., measured) operational characteristic ofthe power system may be determined. With reference to FIG. 1A or 1B,central controller 112 may determine an actual (e.g., measured)operational characteristic of the power system (e.g., based onmeasurements from sensor(s) 116).

In step 504, an expected regulator output may be determined for thearray of power sources. The expected regulator output may be determinedbased on the determined operational characteristics compared to theactual (e.g., measured) operational characteristic. The expectedregulator output may further be determined based on a regulation number.The regulation number may be the number of power sources in the array ofpower sources (e.g., if regulator power is the expected regulatoroutput), the number of power sources in a string (e.g., if regulatorvoltage is employed), or the number of strings (e.g., if regulatorcurrent is employed). With reference to FIG. 1A or 1B, centralcontroller 112 may determine an expected regulator output based on oneor more of the determined operational characteristics of power system100. As mentioned above, the determined operational characteristics ofpower system 100 may comprise at least one of output voltage, outputcurrent, or output power of array of power sources 102.

In step 506, a power regulation signal relating to (e.g., indicating)the expected regulator output may be transmitted to at least some of thepower regulators in the array of power sources. In some examples, theexpected regulator output may be common to all power regulators 110, andthe signal may be broadcasted to all power regulators 110 in the arrayof power sources 102. With reference to FIG. 1A or 1B, centralcommunications module 114 in central module 101 may transmit, to powerregulators 110 in array of power sources 102, a broadcast regulatingsignal relating to (e.g., indicating) the expected regulator output. Insome examples, the expected regulator output may be common to all powerregulators 110 in string 106 of power regulators 110, and the signal maybe multicast to power regulators 110 in that string. With reference toFIG. 1A or 1B, central communications module 114 of central module 101may transmit to power regulators 110 (e.g., power regulators 110-21,110-22, 110-23, . . . , 110-2N in string 106-2), a multicast regulatingsignal relating to (e.g., indicating) the expected regulator output.

In step 508, the power regulation signal relating to (e.g., indicating)the expected regulator output may be received by at least one powerregulator 110 of power source 108 in array of power sources 102. Withreference to FIG. 1C, regulator communications module 124 in powerregulator 110 may receive the signal relating to (e.g., indicating) theexpected regulator output.

In step 510, for each power regulator that receives the power regulationsignal relating to (e.g., indicating) the expected regulator output, aregulator operational characteristic may be increased, decreased, ormaintained based on the received regulation signal and based on one ormore power production characteristics of the power regulator. Forexample, the expected regulator output may relate to output power, theregulator operational characteristic may be regulator output power, andthe power production characteristic may be the MPP of respective powerregulator 110 (e.g., of the respective power source of the powerregulator). In such an example, power regulator 110 may output theminimum between the received expected regulator output and the MPP. Withreference to FIG. 1C, regulator controller 120 may increase, decrease,or maintain the output power of a respective power regulator 110 basedon at least one of the received regulation signal corresponding to theexpected regulator output, based on the output power of power regulator110, or based on the MPP of the respective power source 108. Regulatorcontroller 120 may increase, decrease, or maintain the output power of arespective power regulator 110 based on the received regulation signalrelating to (e.g., indicating) the expected regulator output, based onthe output power of power regulator 110, or the operating temperature ofpower regulator 110 (e.g., regulator controller 120 may direct powerconverter 122 to increase output power if the temperature of powerregulator 110 is above a determined level).

The power regulation indication may be a change indication. A changeindication may be an increase indication, a decrease indication, ano-change indication, or any combination thereof. Based on receiving anincrease indication or a decrease indication, each power regulator 110may use an output increase function or an output decrease function(e.g., stored therein) to increase or decrease a regulator operationalcharacteristic accordingly. Reference is now made to FIGS. 6A, 6B and6C, which illustrate an example of power regulation in an array of powersources, where the power regulation indication for power regulators 110(e.g., in one of strings 106 or in array of power sources 102) may be achange indication. FIG. 6A illustrates an example of an output increasefunction 610. Output increase function 610 in FIG. 6A may be anon-linear decreasing function of percentage of power increase versusregulator operational characteristic of power regulator 110. Theregulator operational characteristic may be output power, outputvoltage, output current, operating temperature, converter duty cycle,output frequency (e.g., if power regulator 110 is a micro-inverter),switching frequency, or a figure of merit incorporating some or all ofthe above mentioned regulator operational characteristics. Such a figureof merit may be a weighted average of normalized values of some or allof the above-mentioned characteristics. A controller (e.g., regulatorcontroller 120 of FIG. 1C) may control one or more regulator operationalcharacteristics of power regulator 110, based on receiving an increaseindication. In the example of FIG. 6A, output increase function 610 maybe a decreasing function of percentage of output voltage increase versusregulator operational characteristic or percentage of output currentincrease versus regulator operational characteristic. Output increasefunction 610 may be a constant, a linear function, a polynomial, or anexponential or a logarithmic decreasing function. Output increasefunction 610 may be implemented as a Look Up Table (LUT), as a vector ofparameters, or a combination thereof. Since output increase function 610may be a decreasing function of a regulator operational characteristic,a higher regulator operational characteristic may correspond to a lowerpercentage of power increase.

In the following example, increase function 610 may be a function ofpercentage of power increase versus regulator output power. The outputpower of a first power regulator (e.g., power regulator 110-11, asillustrated in FIG. 1A), may be 500 W and the output power of a secondpower regulator (e.g., power regulator 110-12, as illustrated in FIG.1A) may be 300 W, which may result in a difference of 200 W. Both powerregulators may operate according to output increase function 610. Bothpower regulators may receive an increase indication. Based on outputincrease function 610, the first power regulator (e.g., power regulator110-11) may increase the output power by 6% and the second powerregulator (e.g., power regulator 110-12) may increase the output powerthereof by 12%. Consequently, the first power regulator may output 530 Wand the second power regulator may output 336 W, which may result in adifference of 194 W. Thus, the difference between the power produced bythe first power regulator and the second power regulator may be reduced.The reduction of the difference may improve the balance of powerproduction (e.g., the distribution of power). A power regulator 110 mayincrease the output power until the respective MPP is reached.

FIG. 6B illustrates an example of a decrease function 620 in accordancewith aspects of the disclosure herein. In the example of FIG. 6B, outputdecrease function 620 may be a non-linear increase function ofpercentage of power decrease versus regulator operational characteristicof power regulator 110. A controller (e.g., regulator controller 120 ofFIG. 1C) may control one or more regulator operational characteristicsof power regulator 110 based on receiving a decrease indication. Outputdecrease function 620 may be an increasing function of percentage ofvoltage decrease versus regulator operational characteristic orpercentage of current decrease versus regulator operationalcharacteristic. Also, output decrease function 620 might not be alogarithmic function. Output decrease function 620 may be a constant, alinear function, a polynomial, or a logarithmically increasing function.Output decrease function 620 may be implemented as a Look Up Table(LUT), as a vector of parameters, or a combination thereof. Since outputdecrease function 620 may be an increasing function of a regulatoroperational characteristic, a higher regulator operationalcharacteristic may correspond to a higher percentage of power decrease.

The increase function 610, decrease function 620, or both, may be changewith the lifetime of power regulator 110. For example, increase function610 may be scaled down as the lifetime of power regulator 110 increases.Thus, the percentage increase of the regulator operationalcharacteristic may decrease as the lifetime of power regulator 110increases. Similarly, decrease function 610 may be scaled up as thelifetime of power regulator 110 increases. Thus, the percentage decreaseof the regulator operational characteristic may increase as the lifetimeof power regulator 110 increases. Scaling the increase function 610,decrease function 620, or both based on the lifetime of power regulator110 may increase the MTBF.

In the following example, output decrease function 620 may be a functionof percentage of power decrease versus regulator output power. In FIG.6B, the output power of a first power regulator may be 500 W and theoutput power of a second power regulator may be 300 W, which may resultin a difference of 200 W. Both power regulators may operate according tooutput decrease function 620. Both power regulators may receive adecrease indication. Based on output decrease function 620, the firstpower regulator may decrease the output power by 35% and the secondpower regulator may decrease the output power by 28%. Consequently, thefirst power regulator may output 370.37 W and the second power regulatormay output 234.37 W, which may result in a difference of 136 W. Thus,the difference between the power produced by the first power regulatorand the second power regulator may be reduced. The reduction of thedifference may improve the balance of power production (e.g., thedistribution of power).

It should be appreciated that the output increase function and theoutput decrease function might not be the same type of function. Forexample, the output increase function may be a constant function and theoutput decrease function may a polynomial. Furthermore, output increasefunction 610 and output decrease function 620 may be a percentage ofpower increase versus a regulator operational characteristic. The outputincrease function and the output decrease function may relate toabsolute or relative values of regulator operational characteristics,and may also be a multi-dimensional function of a regulator operationalcharacteristic as a function of two or more regulator operationalcharacteristics. For example, the output increase function may relate toincrease of output voltage as a function of output power and operatingtemperature. As a further example, the output decrease function mayrelate to decrease of output voltage as a function of output current andoperating temperature. The examples described above are present solelyfor illustration purposes and should not be considered limiting. Forexample, instead of percentage increase or percentage decrease, theincrease function or decrease function of a power regulator 110 mayspecify an increase factor or a decrease factor as a function ofregulator operational characteristics.

According to aspects of the disclosure herein, central module 101 maytransmit one of an increase indication or a decrease indication. Centralmodule 101 may transmit an increase indication (e.g., periodically,based on determined input power compared to actual (e.g., measured)input power, based on determined input voltage compared to actual (e.g.,measured) input voltage, based on determined input current compared toactual (e.g., measured) input current). Power regulator 110 may increasethe regulator operational characteristic according to the outputincrease function (e.g., output increase function 610). Betweenreceptions of increase indications, power regulators 110 may decreasethe regulator operational characteristic according to the outputdecrease function (e.g., output decrease function 620). According toaspects of the disclosure herein, central module may transmit a decreaseindication. Power regulator 110 may decrease the regulator operationalcharacteristic according to the output decrease function (e.g., outputincrease function 402). Between receptions of decrease indications,power regulators 110 may increase the regulator operationalcharacteristic according to the output increase function (e.g., outputincrease function 400).

FIG. 6C depicts a method for regulating power in an array of powersources, such as array of power sources 102, based on at least one of anoutput increase indication, an output decrease indication, or ano-change indication, as described above in conjunction with FIGS. 6Aand 6B. In step 630, a change to an input (e.g., input voltage, inputcurrent, input power) of central module 101 (e.g., increase, decrease,or no-change) may be determined based on the determined and actual(e.g., measured) operational characteristics of a power system. Withreference to FIGS. 1A and 1B, central controller 112 may determine achange to an input of central module 101 (e.g., based on measurementsfrom sensor(s) 116).

In step 640, a change indication may be determined for the powerregulators in an array of power sources based on the determined changeto the input of central module 101. This change indication may be anincrease indication, a decrease indication, or a no-change indication ofthe determined regulator output characteristic (e.g., regulator outputvoltage, regulator output current, or regulator output power). Withreference to FIGS. 1A and 1B, central controller 112 may determine achange indication for power regulators 110 in array of power sources 102based on the determined change to the input of central module 101.

In step 650, a power regulation signal relating to (e.g., indicating)the determined change indication may be transmitted to at least some ofpower regulators 110 in array of power sources 102. The regulationsignal may be a broadcast signal, a multicast signal, or a unicastsignal. With reference to FIGS. 1A and 1B, central communications module114 may transmit, to at least some of power regulators 110, a regulationsignal relating to the change indication determined by centralcontroller 112.

In step 660, the power regulation signal relating to (e.g., indicating)the determined change indication may be received by at least one powerregulator 110, associated with a power source 108, of the plurality ofthe power regulators in array of power sources 102. With reference toFIG. 1C, regulator communications module 124 of at least one of powerregulators 110 may receive the regulation signal relating to thedetermined change indication.

In step 670, each power regulator 110 in array of power sources 102 thatreceived the power regulation signal may change or maintain theregulator operational characteristics based on the received changeindication, and based on an output increase function or output decreasefunction. With reference to FIG. 1C, regulator controller 120 may changeor maintain the regulator operational characteristics of regulator 120based on the change indication received by regulator communicationsmodule 124, and based on an output increase function, such as outputincrease function 610 (FIG. 6A), or an output decrease function, such asoutput decrease function 620 (FIG. 6B).

As described above, some power regulators 110 (e.g., power regulators110-11, 110-12, . . . , 110-1M) may be connected in series, thusdefining a string of power sources 108 (e.g., string 106-1). In such astring, the current flowing through power regulators 110 may be equal.However, in some examples, the power produced by each one of powerregulators 110 may differ, and each one of power regulators 110 mayproduce a different voltage (e.g., when the string produces maximumpower). In some examples, the differences in voltage or power may besignificant where one of power regulators 110 in the string producessignificantly more power than another one of power regulators 110 (e.g.,where power production between power regulators 110 in the string ofpower sources 108 may be unevenly distributed). As mentioned above, theuneven distribution of power production may result in an increase intemperature of some power regulators 110, which may increase theprobability of regulator failure and damage (e.g., a reduction in theMean Time Between Failures—MTBF), and may even result in fire. Accordingto aspects of the disclosure herein, each one of power regulators 110may employ a respective characteristic curve stored therein, which maycomprise a droop over an operating range. The characteristic curve maydefine a relationship between two or more determined outputcharacteristics of the power regulator. In particular, the droop in thecharacteristic curve may define a one-to-one correspondence betweendetermined output characteristics of a power regulator (e.g. over aselected range of currents, voltages, or powers). A droop in acharacteristic curve, discussed below, may reduce the difference betweenthe determined output characteristics of power regulators 110 in thestring of power sources 108.

Reference is now made to FIGS. 7A and 7B, which are examples ofregulator characteristic curves of two power regulators 110, where thetwo power regulators are connected in series (e.g., a series stringcomprised of two power sources), in accordance with aspects of thedisclosure herein. In FIGS. 7A and 7B, the regulator characteristiccurves may be current versus voltage curves (I-V curves). These I-Vcurves may define the relationship between output voltages and outputcurrents of power regulator 110. Power regulator 110 may produce poweraccording to the I-V curve associated with power regulator 110. FIG. 7Adepicts an I-V curve 702 of a first power regulator and an I-V curve 704of a second power regulator, where both power regulators may beconnected in series in the same string of power regulators. I-V curve702 and I-V curve 704 may be determined, stored, or received by thepower regulator. As illustrated in FIG. 7A, both power regulators mayproduce (e.g., at a particular moment or over a time period) the samecurrent, Iout, since the regulators may be connected in series. However,there may be multiple voltages corresponding to Iout on I-V curve 702and on I-V curve 704, which may correspond to the sum of voltagesproduced by the series connection of the first and the second powerregulators. In FIG. 7A, the first power regulator may operate at point706 on curve 702, which may correspond to voltage V1 and the secondpower regulator may operate at point 708 on curve 704, which maycorrespond to voltage V2. In the example in FIG. 7A, point 708 may be anexample of the MPP at which the second regulator may operate. Thevoltage difference between V2 and V1 may be depicted in FIG. 7A as ΔV₁₂.

FIG. 7B depicts an I-V curve 702′ of a third power regulator and an I-Vcurve 704′ of a fourth power regulator. In FIG. 7B, I-V curve 702′comprises a droop 710 and curve 704′ comprises a droop 712, where bothdroops are over a selected range of currents in which each powerregulator 110 may operate. Droop 710 on I-V curves 702′ and droop 712 onI-V curve 704′ may define a one-to-one correspondence between voltagesand currents over the selected range of currents or voltages. In theexample of FIG. 7B, droop 710 and droop 712 may define the sameone-to-one correspondence between voltages and currents over acorresponding range of currents or voltages. In such examples, onevoltage may correspond to each current. In FIG. 7B, both powerregulators may produce a current Iout. However, both the third powerregulator and the fourth power regulator may operate at the same point714, which may correspond to a voltage V3.

In FIG. 7B, droop 710 of I-V curves 702′ and droop 712 of I-V curve 704′are depicted as the same linear function. However, such linear droopsare described herein as an example only and should not be considered aslimiting. Droops 710 and 712 may be different lines intersecting theY-axis at Imax, however, droops 710 and 712 may intersect the Y-axis atcurrents other than Imax. In some examples, when different droop lines(e.g., different slopes) are employed, the operating voltage of eachregulator may be different (e.g., a V1′ for the first regulator, and V2′the second regulator), but the difference between these voltages (e.g.,ΔV′₁₂) may be smaller than if no droops were employed (e.g.,ΔV′₁₂<ΔV₁₂). The droops may be logarithmic functions, polynomialfunctions, or the like. Curves which comprise droops, such as droop 710,over the operating current of power regulators 110 in a string mayreduce the maximum possible difference of output voltages or the outputpower of power regulators 110 in the same string.

FIGS. 7A and 7B illustrate characteristics curves for regulating powerin a string 106 of power regulators 110 where power regulators 110 maybe connected in series (e.g., as similarly depicted in FIG. 1A).However, as depicted in FIG. 1B, in some examples, power regulators 110may be connected in parallel in string 106. When string 106 is comprisedof power regulators 110 connected in parallel, the voltage produced byeach power regulator 110 in the string may be equal. The current orpower produced by each power regulator 110 may differ. Thus, the powerproduction between power regulators 110, connected in parallel in string106 of power source 108, might not be distributed evenly. According toaspects of the disclosure herein, and as described above in conjunctionwith FIGS. 7A and 7B, each one of power regulators 110 may employ acharacteristics curve stored therein, which may comprise a droop over aselected range of the output characteristics of power regulators 110.

Reference is now made to FIGS. 8A and 8B, which depicts examples ofcharacteristic curves of two power regulators 110, where the two powerregulators 110 are connected in parallel (e.g., in a parallel string oftwo power sources). In FIGS. 8A and 8B, the characteristic curves may beI-V curves, which may define a relationship between output voltages andoutput currents of the two power regulators 110. Each power regulator110 may produce power according to the I-V curve associated with powerregulator 110. FIG. 8A depicts I-V curve 802, which may be associatedwith a first power regulator, and I-V curve 804, which may be associatedwith a second power regulator. The first power regulator and the secondpower regulator may be connected in parallel in the same string of powerregulators 110, as illustrated in FIG. 1B. Both power regulators mayproduce a voltage, Vout. However, there may be multiple currentscorresponding to Vout on I-V curve 802 and I-V curve 804, which maycorrespond to the sum of currents produced by the parallel connection ofthe power regulators. As illustrated in FIG. 8A, the first powerregulator may operate at point 806 on curve 802, which may correspond toa current I1. As further illustrated in FIG. 8A, the second powerregulator may operate at point 808 on curve 804, which may correspond toa voltage I2. The difference between I2 and I1 may be depicted in FIG.8A as ΔI₁₂.

FIG. 8B depicts I-V curve 802′, stored in a third power regulator, andI-V curve 804′, stored in a fourth power regulator. In FIG. 8B, I-Vcurve 802′ comprises a droop 810 and curve 804′ comprises a droop 812,wherein droop 810 and droop 812 are both over a selected range ofcurrents or voltages in which each of power regulator 110 operates.Droop 810 on I-V curve 802′ and droop 812 on curve 804′ may identify aone-to-one correspondence between voltages and currents over theselected range of currents or voltages. As illustrated in FIG. 8B, droop810 and droop 812 identify the same one-to-one correspondence betweenvoltages and currents over a corresponding range of currents orvoltages. As such, there may be one current corresponding to eachvoltage. As illustrated in FIG. 8B, both power regulators may produce avoltage Vout. However, both the third power regulator and the fourthpower regulator may operate at the same point 814, which may correspondto a current Tout. Droops 810 and 812 may be different linesintersecting on the X-axis at Vmax, however droops 810 and 812 mayintersect the X-axis at voltages other than Vmax. In some examples,different droop lines may be employed and the operating point of eachregulator may be different, but the difference between the correspondingcurrents may be smaller than when droops might not be employed. Similarto droops 710 and 712, as illustrated in FIG. 7B, droops 810 and 812 maybe linear logarithmic functions, polynomial functions, or the like.Curves which comprise droops, such as droop 810, over the operatingcurrent of power regulators 110 in string 106 may reduce the maximumpossible difference between output voltages or the output power of thepower regulators in the string.

For examples, FIGS. 7A-7B, and 8A-8B describe using a droop in an I-Vcurves of a power regulator 110. A droop may be used in othercharacteristic curves of a power regulator 100. A characteristic curvemay relate a measured operational characteristic to a controlledoperational characteristic. The measured operational characteristic maybe an input voltage (Vin), an output voltage (Vout), an input current(Iin), an output current (Tout), an input power (Pin), an output power(Pout) regulator temperature, a lifetime, a duty cycle, an inputfrequency (e.g., frequency may be zero in case of DC input), an outputfrequency (e.g., may be zero in case of DC output), or a switchingfrequency. The controlled operational characteristic may also be Vin,Vout, Iin, Tout, Pin, Pout, a regulator temperature, a lifetime, a dutycycle, an input frequency, an output frequency, or a switchingfrequency. A selection of the measured operational characteristic andthe controlled operational characteristic may relate to a performance(e.g., efficiency, losses, lifetime) of power regulator 110. Forexample, in case power converter 122 in power regulator 110 is a buckconverter (or operates as a buck converter), the measured operationalcharacteristic may be a temperature and the controlled operationalcharacteristic may be Tout (e.g., since Tout may be a factor in lossesof a buck converter). In case power converter 122 in power regulator 110is a boost converter (or operates as a boost converter), the measuredoperational characteristic may be a temperature and the controlledoperational characteristic may be Vout (e.g., since Vout may be a factorin losses of a boost converter).

Reference is now made to FIGS. 9A-9E which illustrate examples ofvarious characteristic curves which may be used to reduce differencesbetween operational characteristics of power regulators 110 in an arrayof power regulators 102, in accordance with aspects of the disclosureherein. FIG. 9A describes a characteristic curve 850, which is anexample of a characteristic curve of output voltage (Vout) versus power.Characteristic curve 850 bay be a piecewise linear function. FIG. 9Bdescribes characteristic curve 852, which is an example of acharacteristic curve of output power versus lifetime of the powerregulator 110. Characteristic curve 852 may have a linear section 854, anon-linear section 856, and a constant section 858. The lifetime of thepower regulator 110 may be measured, for example, in hours, days, oryears of operation. The lifetime measurement may be weighted by theoperating temperature, operating power, output voltage, or the like. Forexample, a power regulator 110 that operated for an hour at atemperature of 80 degrees centigrade may have a measured lifetime whichwill be higher than a power regulator 110 that operated for an hour at atemperature of 70 degrees centigrade. A power regulator 110 thatoperated for a day with an output voltage of 90V, may have a measuredlifetime which will be higher than a power regulator 110 that operatedfor a day with an output voltage of 80V.

FIG. 9C describes a characteristic curve 860, which is an example of acharacteristic curve of output current (Tout) versus power temperature(e.g., operating temperature, ambient temperature). Characteristic curve860 may be a piecewise linear curve. FIG. 9D describes a characteristiccurve 866, which is an example of a characteristic curve of power versuspower temperature. Characteristic curve 862 may be a non-linear curve. Acharacteristic curve according to the disclosure herein may be amultidimensional curve. FIG. 9E described a multidimensionalcharacteristic curve 864 of output power versus output voltage andtemperature. Power regulator 110 may determine the output power based onthe combination of measured output voltage and measured temperature.According to the disclosure herein, a power regulator 110 may control anoperational characteristic based on more than one characteristic curve.For example, power regulator 110 may control an operationalcharacteristic based on a first characteristic curve (e.g., forbalancing power production), and control a second operationalcharacteristic based on a second characteristic curve. For example,power regulator 110 may control Vout based on temperature for balancingpower production, and may control Vin based on Vout (e.g., for MPPoperation). For example, power regulator 110 may control Pout based onlifetime for balancing power production, and may control Vout based ontemperature.

The examples discussed above in conjunction with FIGS. 1A-1C, 2, 3A-3E,4A-4D, 5, 6A-6C, 7A-7B, 8A-8B, 9A-9E described power productionbalancing. However, according to the disclosure herein, power sources108 may also be power sinks (e.g., energy storage devices such asbatteries, capacitors, or flywheels), or may be replaced with powersinks. In some examples, power balancing may be associated withbalancing power consumption by power sinks (e.g., power storage device,such as batteries, during charging). For example, referring back toFIGS. 1A and 1B, each one of power regulators 110 may be abi-directional regulator configured to either draw power from the powersink or to provide power to the power sink. Central module 101 may beconfigured to provide power to array of power sources 102. When powerregulators 110 provide power to the power sinks, the regulationindication may relate to charging power, charging current, or chargingvoltage of the power sink. For example, balancing the charging and thedischarging of the power sources (or power sinks) in an array of powersources (or power sinks) may also comprise balancing the number ofcharge and discharge cycles of the power sources (or power sinks) in thearray.

In an array of power sources, such as array of power sources 102depicted in FIGS. 1A and 1B, one or more of power regulators 110 mayfail or create a short circuit. In some examples, the resistance may bereduced in the string where the failed power regulator 110 is connected,and power from parallel strings may be diverted to the shorted string.Therefore, a large current may flow through the string in which theshorted power regulator may be located, and the temperature of the powerregulators in that string may increase. Such an increase in temperaturemay lead to overheating and may increase the risk of fire.

Reference is now made to FIG. 10 , which depicts power system 100, inaccordance with the disclosure herein. As illustrated in FIG. 10 , powerregulators 110 in string 106-1 may be short circuited (e.g., due tomalfunction). Therefore, the currents of strings 106-2, . . . , 106-N,or portions thereof, may be directed to string 106-1 instead of centralmodule 101, as indicated by arrows 900-1, 900-2, 900-3, and 900-4.Directing current from one string to other strings may be referred toherein as “power leakage” or “fault”. Power leakage may result from aground fault occurring (e.g., when a point of string 106 shorts toground) or from a line-to-line fault occurring (e.g., when two points ofthe same string or two points on different strings are shorted). Duringpower leakage, the resistance of the shorted string may be reduced. Insome examples, a shorted string may turn into a power load instead of apower source.

Central controller 112 of central module 101 may be configured to detecta power leakage. For example, central module 101 may detect a powerleakage based on a comparison of determined input voltage, inputcurrent, or input power, and actual input voltage, input current, orinput power. Central controller 112 may be configured to control centralcommunications module 114 to repeatedly transmit an expected regulatoroutput or an increase indication (e.g., a determined number of times orfor a determined time-period). However, central controller 112 maydetermine, based on signals relating to (e.g., indicating) the inputvoltage or input current of central module 101 (e.g., received fromsensors(s) 116), that the actual input voltage, input current, or inputpower might not match the determined input voltage, input current, orinput power. The determined input voltage, input current, or input powermay be pre-defined or may be defined by determined output power whencentral module 101 is an inverter (e.g., inverter 1100, as illustratedin FIG. 12 ). Central controller 112 may be configured to determine thata power leakage exists and may transmit, via central communicationsmodule 114, an expected regulator output with a determined safe value.In some examples, the safe value may be predetermined (e.g., a valueless than 100 W and preferably less than 15 W). In some examples, thesafe value may be either a percentage of the expected input power at theinput of central module 101 or a percentage of the available input powerat input terminals 113-1 and 113-2 of central module 101 (e.g., lessthan 10% from the available input power).

Each one of power regulators 110 may be configured to transmit a signalrelating to (e.g., indicating) the regulator operational characteristics(e.g., output voltage, output current, output power, operatingtemperature, or DC-DC converter duty cycle). Central communicationsmodule 114 may be configured to receive these signals from powerregulators 110. Central controller 112 may determine if a power leakageexists based on the received signals relating to (e.g., indicating) theregulator operational characteristics. For example, central controller112 may be configured to sum the powers produced by power regulators 110based on the received signals from each power regulator 110, and tocompare the sum to a measured input power at inverter input terminals113-1 and 113-2 (e.g., as sensor(s) 116). Based on the sum of powersbeing higher than the measured input power, central controller 112 maydetermine that a power leakage exists. In some examples, a power leakagemay indicate that at least one of power regulators 110 might not producethe indicated power, although that power regulator may transmit anindication that it produces power. Based on determining that a powerleakage exists, central controller 112 may be configured to transmit,via central communications module 114, an expected regulator output witha determined safe value.

If one or more power regulators 110 of strings 106 in array of powersources 102 is short circuited, the voltage across the correspondingshort circuited string may also be reduced. Consequently, the voltageacross the other strings and across input terminals 113-1 and 113-2 ofcentral module 101 may also be reduced. For example, if string 106-1 isshort circuited, the voltage across input terminals 113-1 and 113-2 ofcentral module 101 may be reduced. Consequently, the output voltage ofeach of power regulator 110 may also be reduced.

Central controller 112 may be configured to determine that a powerleakage exists based on receiving signals from power regulators 110indicating to the output voltages thereof, determining a sum of theoutput voltages received from each power regulator 110, and comparingthe sum to the determined input voltage of central module 101. Based onthe sum of voltages being lower than the input voltage determined bycentral module 101, central controller 112 may determine that a powerleakage exists. Central controller 112 may be configured to determinethat a power leakage exists based on the sum of voltages being lowerthan a predetermined value (e.g., equal to or less than 100V, equal toor less than 50V) or a percentage of the expected input voltage (e.g.,equal to or less than 50%, equal to or less than 10% of the expectedinput voltage).

Central controller 112 may be configured to determine (e.g., based onreceived signals relating to (e.g., indicating) the output voltage,output current, or output power) whether the currents of powerregulators 110 (e.g., power regulators 110-11, 110-12, 110-13 . . . ,110-1M in string 106-1) may be negative. In some examples, centralcontroller 112 may be configured to determine, based on the receivedsignals, whether a power regulator (e.g., power regulator 110-12) mayfail to produce power. Central controller 112 may be configured todetermine that a power leakage exists based on not receiving a signalfrom some of power regulators 110 (e.g., from power regulator 110-12).In such instances, central controller 112 may determine that a powerleakage exists. Central controller 112 may be configured to transmit,via central communications module 114, an expected regulator output witha determined safe value.

If a string experiences a partial short circuit, power regulators 110may increase the output voltage thereof to compensate for the faultypower regulator. For example, power regulator 110-12 in string 106-1 maybe short circuited. Consequently, the output voltage of the other powerregulators 110 in string 106-1 may increase to compensate for powerregulator 110-12 (e.g., the remaining power regulators 110 in string106-1 may output the maximum voltage). Central controller 112 may beconfigured to determine that a power leakage exists based on receivingsignals from power regulators 110 relating to (e.g., indicating) theoutput voltages and based on using the received signals to identifypower regulators that may generate the maximum output voltage.

Central module 101 (e.g., using central controller 112) may beconfigured to determine that a power leakage exists based on measuredloop resistance of array of power sources 102. For example, if centralmodule 101 is an inverter, central controller 112 may control aswitching converter to produce a determined voltage at input terminals113-1 and 113-2 of central module 101. Central controller 112 may beconfigured to receive signals indicating voltage or current measurementsfrom sensor(s) 116. Based on the voltage or current measurements,central controller 112 may determine the loop resistance of array ofpower sources 102 (e.g., by dividing the measured voltage by themeasured current). Furthermore, central controller 112 may determine anexpected resistance based on the determined voltage at input terminals113-1 and 113-2, and based on the measured current. Based on thedetermined loop resistance being lower than the expected resistance,central controller 112 may determine that a power leakage exists.

The risks resulting from a fault may be reduced by limiting the outputcurrent or power for low output voltages of power regulators 110.Reference is now made to FIG. 11 , which depicts an example of acharacteristic curve 1000. In FIG. 11 , characteristic curve 1000 may bean output current versus output voltage (I-V) curve that is associatedwith a power regulator 110. I-V curve 1000 may illustrate a one-to-onerelationship between output voltage and output current, as indicated byincline 1002, over an output voltage Vlow and an output voltage Vsafe,where Vsafe may be higher than Vlow (e.g., Vlow may be zero or higher).When a power regulator may be short circuited, the output voltage of thepower regulator may be reduced. Based on the output voltage of the powerregulator being below Vsafe, the output current may also be reducedaccording to the one-to-one relationship (e.g., incline 1002) on curve1000. Thus, the current flowing out of the string may also be reduced,thereby reducing the risks resulting from a fault.

As mentioned above, central module 101, as illustrated in FIGS. 1A and1B, may be an inverter configured to convert DC power received fromarray of power sources 102. Reference is now made to FIG. 12 , whichillustrates an example in which central module 101 is an inverter. Asillustrated in FIG. 12 , inverter 1100 may comprise power converter1102, inverter communications module 1104, inverter controller 1106,inverter input terminals 1101-1 and 1101-2, and inverter outputterminals 1103-1 and 1103-2. Inverter 1100 may comprise one or moresensors, such as input voltage sensor 1108, input current sensor 1110,output voltage sensor 1112, output current sensor 1114 and temperaturesensor 1116. Inverter 1100 may comprise string current sensors, such asstring current sensors 1118-1, 1118-2, . . . , 1118-N. Power converter1102 may comprise switching converter 1120. Power converter 1102 maycomprise transformer 1122. Power converter 1102 may comprise inputcapacitor 1124 or output capacitor 1126. Transformer 1122 may compriseprimary windings 1128, secondary windings 1130, wherein primary windings1128 and secondary windings 1130 may be wound around common core 1132.Common core 1132 may comprise of one or more ferromagnetic materials.

Inverter controller 1106 may be connected to switching converter 1120and to inverter communications module 1104. Inverter controller 1106 maybe further connected input voltage sensor 1108, input current sensor1110, output voltage sensor 1122, output current sensor 1114, andtemperature sensor 1116. The input of switching converter 1120 may beconnected to inverter input terminals 1101-1 and 1101-2. The output ofswitching converter 1120 may be connected to primary windings 1128 oftransformer 1122. Secondary windings 1130 of transformer 1122 may beconnected to inverter output terminals 1103-1 and 1103-2 of inverter1100. Input capacitor 1124 may be connected across inverter inputterminals 1101-1 and 1101-2. Output capacitor 1126 may be connectedacross inverter output terminals 1103-1 and 1103-2. Input voltage sensor1108 may be connected between inverter input terminals 1101-1 and1101-2. Output voltage sensor 1112 may be connected between inverteroutput terminals 1103-1 and 1103-2. Input current sensor 1110 may beconnected to inverter input 1101-1. Output current sensor 1114 may beconnected to inverter output 1103-1. Inverter controller 1106 may beconnected to string current sensor 1118-1, 1118-2, . . . , 1118-N.

Switching converter 1120 may be implemented by a transistor half-bridge,full-bridge (e.g., an H-Bridge), flying capacitor, cascaded-H-bridge,Neutral Point Clamped (NPC), A-NPC, or a T-type NPC inverting circuitemploying two or more conversion levels. Switching converter 1120 may beoperated (e.g., by inverter controller 1106) by employing a pulse widthmodulation (PWM) signal. Switching converter 1120 may operate at aswitching frequency between 1 Hz-10 MHz. For example, where switchingconverter 1120 comprises one or more power field-effect transistors(“FET”), switching converter 1120 may be operated at a switchingfrequency between 16 KHz-200 KHz (e.g., frequencies at which switchinglosses may be greatly reduced for power FETs operating in a resonantcircuit). In some examples, switching converter 1120 may operate at aswitching frequency of 30 KHz.

In some examples, transformer 1122 may be a step-up transformer in whichthe number of windings in secondary windings 1130 may be larger than thenumber of windings in primary windings 1128. In some examples,transformer 1122 may be a step-down transformer in which the number ofwindings in secondary windings 1130 may be smaller than the number ofwindings in primary windings 1128. A voltage on a secondary side of atransformer (i.e., on secondary windings 1130) may be given byVsec=Vprim*N/M, where Vsec may represent a voltage on the secondaryside, Vprim may represent a voltage on the primary side of thetransformer (e.g., primary windings 1122), M may be the number of turnsof windings on the primary side, and N may be the number of turns ofwindings on the secondary side. In some transformers, when M is equal toN, Vsec may be equal to Vprim (i.e., the output voltage is equal to theinput voltage). In a step-up transformer, when M is greater than N, Vsecmay be greater than Vprim (i.e., the output voltage is larger than theinput voltage). In a step-down transformer, when M is less than N, Vsecmay be less than Vprim (i.e., the output voltage is smaller than theinput voltage).

Transformer 1122 may also provide galvanic isolation between inverterinput terminals 1101-1 and 1101-2, and inverter output terminals 1103-1and 1103-2. In addition, one or both of primary windings 1128 orsecondary windings 1130 may be encapsulated in a resin, such as epoxy(e.g., cast in a vacuum to reduce the number of air bubbles). Primarywindings 1128 and secondary windings 1130 may be wound around commoncore 1132, which may comprise ferromagnetic materials. Primary windings1128 and secondary windings 1130 may each comprise bifilar windings, andeach one of primary windings 1128 and secondary windings 1130 may bewound on a different leg of common core 1132. In operation, switchingconverter 1120 may receive DC voltage at input terminals 1101-1 and1101-2. Input capacitor 1124 may stabilize the voltage between inverterinputs 1101-1 and 1101-2. Switching converter 1120 may generate a pulsedoutput at the input of transformer 1122. Transformer 1122 may step-up,step-down, or maintain the voltage generated by switching converter1120. Output capacitor 1126 may filter the output from transformer 1122to generate an AC voltage between inverter outputs 1103-1 and 1103-2.

Input voltage sensor 1108 may be configured to measure the voltagebetween inverter input terminals 1101-1 and 1101-2, and to provide ameasurement of the input voltage to inverter controller 1106. Outputvoltage sensor 1112 may be configured to measure the voltage betweeninverter output terminals 1103-1 and 1103-2, and to produce ameasurement of the output voltage to inverter controller 1106. Inputvoltage sensor 1108 or output voltage sensor 1112 may be based on aresistive or capacitive divider, a resistive or capacitive bridge,comparators (e.g., employing operational amplifiers), or the like. Inputcurrent sensor 1110 may be configured to measure the currents throughinverter input terminal 1101-1, and to provide a measurement of theinput current to inverter controller 1106. Output current sensor 1114may be configured to measure the currents through inverter outputterminal 1103-1, and to provide a measurement of the input or outputcurrent to inverter controller 1106. Input current sensor 1110 andoutput current sensor 1114 may comprise a Current Transformer (“CT”)sensor, Hall effect sensor, zero flux sensor, or the like.

Inverter communications module 1104 may be configured to transmit asignal (e.g., communications module 1104 may be a simplex transmitter).The signals may comprise broadcast signals, multicast signals, orunicast signals. Communications module 1104 may also be configured toreceive a signal (e.g., communications module 1104 may be a half-duplexor full-duplex transceiver). Inverter communications module 1104 maytransmit a signal to all power regulators 110, to a group of powerregulators 110 (e.g., to string 106), or to a single power regulator110, as described above in conjunction with FIGS. 1A-1C, 2, 3A-3E,4A-4D, 5, 6A-6C.

Inverter controller 1106 may be configured to control switchingconverter 1120 (e.g., by controlling switches in switching converter1120). Inverter controller 1106 may be configured to provide invertercommunications module 1104 with signals relating to power production inpower system 100 (e.g., signals relating to (e.g., indicating) powerregulation indications such as expected regulator output, increaseindications, decrease indications, or maintain indications). Invertercommunications module 1104 may be configured to receive signals (e.g.,from power regulators 110) relating to (e.g., indicating) powerproduction in power system 100 (e.g., signals relating to (e.g.,indicating) determined regulator operational characteristics of powerregulators 110). The signals relating to (e.g., indicating) powerproduction in power system 100 may be transmitted and receivedperiodically. Inverter controller 1106 may comprise a microcontroller, aField Programmable Gate Array (FPGA), or an Application SpecificIntegrated Circuit (ASIC) that may be configured to carry out a set ofcontrol instructions.

The example in FIG. 12 illustrates components of power converter 1102solely for illustration purposes and is not meant to be limiting. Powerconverter 1102 may comprise multiple intermediate conversion stages(e.g., power converter 1102 may comprise DC-DC-AC-DC-AC conversionstages). The first DC-DC stage may increase the DC voltage generated bya power source 108. The next DC-AC stage may convert the DC voltage to apulsed voltage and may comprise a transformer for stepping up the pulsedvoltage. The pulsed voltage may be rectified in the next AC-DCconversion stage. The rectified voltage may then be converted to apulsed voltage at a determined frequency (e.g., the grid frequency). Themulti-stage power conversion may further include filtering between anyone of the above described stages. In some examples, if inverter 1100receives AC power at input terminals 1101-1 and 1101-2, power converter1102 may include a rectification stage. Employing multi-stage conversiontechniques may reduce the size of magnetic elements (e.g., thetransformers). In some examples, the size of the transformer may bereduced by boosting the DC voltage in the DC-DC conversion stage and byswitching, in the first DC-AC conversion stage, at a relatively highfrequency (e.g., tens of kilohertz, hundreds of kilohertz, or more).

As mentioned above, a power regulation indication may be based one ormore determined operational characteristics of power system 100. Ifcentral module 101, as depicted in FIGS. 1A and 1B, is an inverter, thedetermined operational characteristic(s) of power system 100 mayindicate one or more determined operational characteristics of inverter1100. An inverter operational characteristic may be determined inverterinput power (e.g., pre-defined in inverter specification or defined byrequired output power) compared to actual (e.g., measured) inverterinput power, determined inverter input voltage compared to actual (e.g.,measured) inverter input voltage, or determined inverter input currentcompared to actual (e.g., measured) inverter input current. A determinedinverter operational characteristic may be the determined inverteroutput voltage compared to actual (e.g., measured) inverter outputvoltage, determined inverter output current compared to actual (e.g.,measured) inverter output current, determined inverter output powercompared to actual (e.g., measured) inverter output power, determinedinverter voltage gain compared to actual (e.g., measured) invertervoltage gain, or determined inverter current gain compared to actual(e.g., measured) inverter current gain. A determined inverteroperational characteristic may be determined inverter transresistancecompared to actual (e.g., measured) inverter transresistance ordetermined inverter transconductance compared to actual (e.g., measured)inverter transconductance.

In the example above, inverter 1100 is described as receiving inputpower at input terminals 1101-1 and 1101-2 and as providing output powerat output terminals 1103-1 and 1103-2. However, according to thedisclosure herein, the roles of the input terminals and the outputterminals may be reversed. In some examples, terminals 1103-1 and 1103-2may receive power (e.g., from the grid) and terminals 1101-1 and 1101-2may provide power to the array of power sinks.

As mentioned above, central module 101 may be a combiner. Reference isnow made to FIG. 13 , which illustrates an example in which centralmodule 101 may be a combiner. Combiner 1200 may be configured to connectstrings 106-1, 106-2, . . . , 106-N in parallel. Combiner 1200 maycomprise at least two power busbars 1202-1 and 1202-2. Combiner 1200 maycomprise combiner communications module 1206 and combiner controller1204. Combiner 1200 may comprise voltage sensor 1208, current sensor1210, or temperature sensor 1212. Combiner 1200 may comprise fuses1214-1, 1214-2, . . . , 1214-N, or switches 1216-1, 1216-2, . . . ,1216-N. Combiner 1200 may comprise string current sensors 1218-1,1218-2, . . . , 1218-N. Combiner communications module 1206, voltagesensor 1208, current sensor 1210, temperature sensor 1212, and stringcurrent sensors 1218-1, 118-2, . . . , 1218-N may be connected tocombiner controller 1204. Combiner communications module 1206 may besimilar to inverter communications module 1104, as illustrated in FIG.12 . Voltage sensor 1208 may be similar to output voltage sensor 1112,as illustrated in FIG. 12 . Current sensor 1210 may be similar to outputcurrent sensor 1114, as illustrated in FIG. 12 . Combiner controller1204 may be configured to control combiner communications module 1206 totransmit a signal to power regulators 110. In some examples, combinercontroller 1204 may be configured to control combiner communicationsmodule 1206 to receive a signal from power regulators 110. Power busbars1202-1 and 1202-2 may be configured to connect to a plurality of stringoutput terminals that may exhibit the same (or substantially similar)polarity of a corresponding power bus. Power busbar 1202-1 may connectoutput terminals 111-11, 111-21, . . . , 111-N1 of strings 106-1, 106-2,. . . , 106-N, as illustrated in FIGS. 1A and 1B, to output terminals1222-1 of combiner 1200 via positive power bus 1202-1. Power busbar1202-2 may connect output terminals 111-12, 111-22, . . . , 111-N2 ofstrings 106-1, 106-2, . . . , 106-N, as illustrated in FIGS. 1A and 1B,to output terminal 1222-2 of combiner 1200 via negative power bus1202-2.

If central module 101 is a combiner, the determined operationalcharacteristics of power system 100 may indicate one or more determinedoperational characteristics of combiner 1200. A determined combineroperational characteristic may be similar to the determined inverteroperational characteristics described above. In the example describedabove, combiner 1200 is described as receiving input power fromterminals 111 and providing output power to output terminals 1211-1 and1222-2. However, according to the disclosure herein, combiner 1200 mayreceive power at terminals 1222-1 and 1222-2 and may provide power toterminals 111.

In some examples, both an inverter and a combiner (e.g., inverter 1100and combiner 1200) may be employed for power regulation of power system100. For example, combiner 1200 may be configured to regulate the outputcurrent of power regulators 110 in strings connected thereto, andinverter 1100 may be configured to regulate the output power betweenpower regulators 110 in power system 100 (e.g., according to techniquesdescribed above in conjunction with FIGS. 1A-1C, 2, 3A-3E, 4A-4D, 5 , orany combination thereof). If both inverter 1100 and combiner 1200 areemployed to regulate power in power system 100, the power regulation maybe hierarchical. In a hierarchical system, inverter 1100 may beconnected to a plurality of combiners similar to combiner 1200, whereineach combiner may be connected to a plurality of strings 106. In ahierarchical system, each combiner (e.g., combiner 1200) may beconfigured to regulate the power of the strings (e.g., strings 106)connected thereto according to any one of the options described above.In a hierarchical system, inverter 1100 may be configured to regulatethe combiners according to any one of the options described above. In ahierarchical system, inverter 1100 may identify combiners 1200 as powerregulators 110.

Power regulator 110 may be implemented using a DC-DC converter.Reference is now made to FIG. 14 , which illustrates an example of apower regulator. Power regulator 1300 may comprise a DC-DC converter.Power regulator 1300 may comprise regulator controller 1302, DC-DCconverter 1304, and communications module 1306. Communications module1306 may be a receiver, a transmitter, or a transceiver, similar toregulator communications module 124 illustrated in FIG. 1C. Powerregulator 1300 may comprise one or more sensors, such as input voltagesensor 1308, input current sensor 1310, output voltage sensor 1312,output current sensor 1314, or temperature sensor 1316. Each sensor maybe connected to regulator controller 1302. Input terminals 1318-1 and1318-2 of power regulator 1300 may each be connected to a respective DCpower source 108. Regulator controller 1302 may be connected to DC-DCconverter 1304. Input voltage sensor 1308 may be connected between inputterminals 1318-1 and 1318-2. Output voltage sensor 1312 may be connectedbetween output terminals 1320-1 and 1320-2. Input current sensor 1310may be further connected to input terminal 1318-1. Output current sensor1314 may be further connected to output terminal 1320-1.

Input voltage sensor 1308 may be configured to measure the voltagesbetween input terminals 1318-1 and 1318-2, and to provide a measurementof the input voltage to regulator controller 1302. Output voltage sensor1312 may be configured to measure the voltages between output terminals1320-1 and 1320-2, and to provide a measurement of the output voltage toregulator controller 1302. Input voltage sensor 1308 and output voltagesensor 1312 may comprise a resistive or capacitive divider, a resistiveor capacitive bridge, comparators (e.g., employing operationalamplifiers), or the like. Input current sensor 1310 may be configured tomeasure the currents through input 1318-1, and to provide a measurementof the input current to regulator controller 1302. Output current sensor1314 may be configured to measure the currents through output terminal1320-1, and to provide a measurement of the output current to regulatorcontroller 1302. Input current sensor 1310 and output current sensor1314 may comprise a Current Transformer (CT) sensor, Hall effect sensor,zero flux sensor, or the like.

DC-DC converter 1304 may be configured to convert DC input power fromthe respective DC power source 108 to DC output power at the outputterminals 1320-1 and 1320-2 of power regulator 1300. DC-DC converter1304 may comprise a buck converter, a boost converter, a buck-boostconverter, or a buck and boost converter. The output voltage betweenoutput terminals 1320-1 and 1320-2 may be controlled using a duty cycleof a corresponding pulse-width modulated (PWM) signal. The duty cyclemay be controlled using one or more switches in DC-DC converter 1304.

Communications module 1306 may be configured to receive signals (e.g.,communications module 1306 may be a simplex receiver), and to transmitsignals (e.g., communications module 1306 may be a half-duplex orfull-duplex transceiver). Communications module 1306 may operateaccording to a communications protocol, and may comprise suitablyarranged amplifiers, filters, demodulators, modulators, mixers,analog-to-digital converter (ADC), digital-to-analog converter (DAC),encoders and decoders, and interleavers and deinterleavers. In someexamples, communications module 1306 may be a Power Line Communications(PLC) receiver. However, in some examples, communications module 1306may be a wireless receiver or a line receiver (e.g., a telephone,internet lines, or dedicated lines), and may employ a suitablecommunications protocols (e.g., ZigBee™, Wi-Fi, Ethernet, or variouscellular protocols).

Regulator controller 1302 may be configured to control DC-DC converter1304 (e.g., by alternatively switching switches thereof, or changing theduty cycle of a PWM signal) to increase, decrease, or maintain one ormore of the determined regulator operational characteristics (e.g.,output voltage, output current, output power, operating temperature,duty cycle, or any combination thereof) of DC-DC converter 1304.Regulator controller 1302 may be further configured to receive signalsfrom communications module 1306 (e.g., to receive power regulationindications). Regulator controller 1302 may transmit, to communicationsmodule 1306, signals relating to (e.g., indicating) power production(e.g., voltages, currents) as well as metadata (e.g., power regulatorID, time, measurements, or the like). Regulator controller 1302 may beimplemented based on a microcontroller, a Field Programmable Gate Array(FPGA), or an Application Specific Integrated Circuit (ASIC) that may beconfigured to execute a set of control instructions.

In the example above, power regulator 1300 is described as receivinginput power at input terminals 1318-1 and 1318-2, and as providingoutput power at output terminals 1320-1 and 1320-2. However, accordingto the disclosure herein, the roles of the input and output terminalsmay be reversed. For example, terminals 1320-1 and 1320-2 may receivepower (e.g., from the grid) and terminals 1318-1 and 1318-2 may providepower to the corresponding power sink.

In some examples, power regulator 110 may comprise a DC-AC converter.Reference is now made to FIG. 15 , which illustrates an example of apower regulator. As illustrated in FIG. 15 , power regulator 1400 maycomprise a DC-AC converter. Power regulator 1400 may be similar to powerregulator 1300 illustrated in FIG. 14 , except that power regulator 1400may comprise DC-AC converter 1404 instead of DC-DC converter 1304.

Power regulator 1400 may comprise regulator controller 1402, DC-ACconverter 1404, and communications module 1406. Power regulator 1400 maycomprise one or more sensors, such as input voltage sensor 1408, inputcurrent sensor 1410, output voltage sensor 1412, output current sensor1414, or temperature sensor 1416. Each sensor may be connected toregulator controller 1402. Power regulator 1400 may comprise inputterminals 1418-1 and 1418-2, and output terminals 1420-1 and 1420-2.DC-AC converter 1404 may comprise switching converter 1422. DC-ACconverter 1404 may comprise transformer 1424. DC-AC converter 1404 maycomprise input capacitor 1426 or output capacitor 1428. Transformer 1424may comprise primary windings 1430 and secondary windings 1432. Primarywindings 1430 and secondary windings 1432 may be wound around commoncore 1434. Common core 1434 may comprise of one or more ferromagneticmaterials. In some examples, DC-AC converter 1404 might not employtransformer 1424. If DC-AC converter 1404 does not employ transformer1424, switching converter 1422 may be connected to regulator outputterminals 1420-1 and 1420-2.

Input terminals 1418-1 and 1418-2 of power regulator 1400 may beconnected to a respective DC power source 108. Regulator controller 1402may be connected to DC-AC converter 1422. Input voltage sensor 1408 maybe connected between input terminals 1418-1 and 1418-2. Output voltagesensor 1412 may be connected between output terminals 1420-1 and 1420-2.Input current sensor 1410 may be connected to input terminal 1418-1.Output current sensor 1414 may be connected to output terminal 1420-1.

DC-AC converter 1404 may be similar to DC-AC converter 1120 illustratedin FIG. 12 . Regulator controller 1402 may be configured to controlswitching converter 1422. Switching converter 1422 may be configured togenerate a pulsed output voltage (e.g., a square-wave or a steppedpulsed wave) at the output of switching converter 1422.

Transformer 1424 of DC-AC converter 1404 may be similar to transformer1122 illustrated in FIG. 12 . Transformer 1424 may be a step-uptransformer in which the number of windings in secondary windings 1432may be larger than the number of windings in primary windings 1430.Transformer 1424 may be a step-down transformer in which the number ofwindings in secondary windings 1432 may be smaller than the number ofwindings in primary windings 1430. Transformer 1424 may provide galvanicisolation between converter input terminals 1418-1 and 1418-2, andbetween converter output terminals 1420-1 and 1420-2. At least one ofprimary windings 1430 or secondary windings 1430 may be encapsulated ina resin, such as epoxy. Primary windings 1430 and secondary windings1432 may be wound around common core 1434, which may compriseferromagnetic materials. In some examples, primary windings 1430 andsecondary windings 1432 may each comprise bifilar windings and, as such,each one of primary windings 1430 and secondary windings 1432 may bewound around a different leg of common core 1434. In operation of DC-ACconverter 1404, switching converter 1422 may receive DC voltage atinverter input terminals 1418-1 and 1418-2. Input capacitor 1426 maystabilize the voltage across inverter input terminals 1418-1 and 1418-2.Switching converter 1422 may generate a pulsed output voltage (e.g., asquare-wave or a stepped pulsed wave—similar to switching converter 1120in FIG. 12 ) at the input of transformer 1424. Transformer 1424 maystep-up, step-down, or maintain the voltage generated by switchingconverter 1422. Output capacitor 1428 may filter the output oftransformer 1424 to generate an AC voltage across inverter outputterminals 1420-1 and 1420-2.

Communications module 1406 may be configured to receive signals (e.g.,communications module 1406 may be a simplex receiver), and to transmitsignals (e.g., communications module 1406 may be a half-duplex orfull-duplex transceiver). Communications module 1406 may operateaccording to a communications protocol, and may comprise suitablyarranged amplifiers, filters, demodulators, modulators, mixers,analog-to-digital converter (ADC), digital-to-analog converter (DAC),encoders and decoders, and interleavers and deinterleavers. In someexamples, communications module 1406 may be a Power Line Communications(PLC) receiver. In some examples, communications module 1406 may be awireless receiver or a line receiver (e.g., a telephone, internet lines,or dedicated lines), and may employ a suitable communications protocol(e.g., ZigBee™, Wi-Fi, Ethernet, or various cellular protocols).

Regulator controller 1402 may be configured to control DC-AC converter1404 (e.g., by alternatively switching switches in switching converter1422 or by changing the duty cycle of a PWM signal). Regulatorcontroller 1402 may be further configured to receive signals fromcommunications module 1406 (e.g., to receive power regulationindications). Regulator controller 1402 may transmit, to communicationsmodule 1406, signals relating to (e.g., indicating) power production(e.g., voltages, currents) as well as metadata (e.g., power regulatorID, time, measurements, or the like). Regulator controller 1402 may beimplemented based on a microcontroller, a Field Programmable Gate Array(FPGA), or an Application Specific Integrated Circuit (ASIC) that may beconfigured to carry out a set of control instructions.

In the example described above, power regulator 1400 is described asreceiving input power at input terminals 1418-1 and 1418-2 and asproviding output power at output terminals 1420-1 and 1420-2. In someexamples, the roles of the input and output terminals may be reversed.In some examples, terminals 1420-1 and 1420-2 may receive power (e.g.,from the grid) and terminals 1418-1 and 1418-2 may provide power to thecorresponding power sink.

A system may comprise a plurality of power sources configured togenerate power, and a plurality of power regulators, wherein each powerregulator of the plurality of power regulators comprises: a powerconverter configured to convert input power from a corresponding one ofthe plurality of power sources to output power, a regulator transceiverconfigured to receive at least one power regulation signal, wherein theat least one power regulation signal is associated with regulating anoperational characteristic of the power regulator, wherein the at leastone power regulation signal is one of a broadcast signal or a multicastsignal, and a regulator controller connected to the power converter andthe regulator transceiver, and configured to, based on the at least onepower regulation signal and based on a power production characteristicof the power regulator, control the power converter to increase ordecrease a magnitude of the operational characteristic of the powerregulator. The system may further comprise a central circuit, whereinthe central circuit comprises: a sensor configured to measure at leastone of an input voltage, an input current, an output voltage, an outputcurrent, or an operating temperature of the central circuit, a centralcontroller configured to: determine an operational characteristic of thecentral circuit based on a measurement from the sensor, and determinethe power regulation signal based on the determined operationalcharacteristic of the central circuit, and a central transceiverconnected to the central controller, configured to transmit the powerregulation signal to at least one power regulator of the plurality ofpower regulators. The operational characteristic of the central circuitmay be based on at least one of: a difference or a ratio between apredetermined input voltage and a measured input voltage, a differenceor a ratio between a predetermined input current and a measured inputcurrent, a difference or a ratio between a predetermined input power anda measured input power, a difference or a ratio between a predeterminedoutput voltage and a measured output voltage, a difference or a ratiobetween a predetermined output current and a measured output current, adifference or a ratio between a predetermined output power and ameasured output power, a difference or a ratio between a predeterminedvoltage gain and a measured voltage gain, a difference or a ratiobetween a predetermined current gain and a measured current gain, adifference or a ratio between a predetermined transresistance and ameasured transresistance, or a difference or a ratio between apredetermined transconductance and a measured transconductance.

The power regulation signal comprises a change indication. Each powerregulator of the plurality of power regulators may be further configuredto control its operational characteristic to increase or decrease themagnitude of the operational characteristic of the power regulator basedon the change indication and a corresponding one of an increasefunction, or a decrease function. The power production characteristic ofeach power regulator of the plurality of power regulators comprises atleast one of: a Maximum Power Point (MPP) of the corresponding one ofthe plurality of power sources, a current versus voltage characteristicof the corresponding power source of the plurality of power sources, theincrease function, the decrease function, or an operating temperature.The central circuit may comprise power busbars configured to combineoutputs of the plurality of power regulators. The power regulationsignal may be transmitted, from a central circuit, as the broadcastsignal or the multicast signal to each power regulator of the pluralityof power regulators. The operational characteristic of each powerregulator of the plurality of power regulators may comprise at least oneof an output voltage, an output current, an output power, an operatingtemperature, a duty cycle, an input voltage, an input current, an inputpower, a lifetime, or a frequency. Each power regulator of the pluralityof power regulators may further comprise a sensor connected to theregulator controller, wherein the sensor is configured to measure atleast one of an input voltage, an input current, an output voltage, anoutput current, or an operating temperature of the power regulator, andwherein the regulator controller is further configured to control thepower converter based on a measurement from the sensor. Each powerregulator of the plurality of power regulators may store acharacteristic curve defining a relationship between at least twooperational characteristics of the power regulator, wherein, thecharacteristic curve comprises a droop over an operating range of thepower regulator, and wherein the regulator controller is furtherconfigured to control the power converter to increase, decrease, ormaintain magnitudes of the operational characteristics of the powerregulator based on the characteristic curve. The power converter, ofeach power regulator of the plurality of power regulators, may be adirect current (DC) to direct current (DC-to-DC) converter or a DC toalternating current (DC-to-AC) converter comprising at least a switchingconverter. The plurality of power regulators, connected in series or inparallel, may form a plurality of strings, wherein each of the pluralityof strings comprises a subset of the plurality of power regulators, andwherein each power regulator of the subset is configured to: connect,via input terminals, to the corresponding one of the plurality of powersources, and provide, via output terminals, the output power.

A method may comprise determining, by a central circuit, a powerregulation signal, transmitting, by a transceiver of the central circuitand to at least one power regulator of a plurality of power regulators,the power regulation signal as a broadcast signal or a multicast signal,and based on the power regulation signal transmitted and based on apower production characteristic of the at least one power regulator,causing, by the central circuit, the at least one power regulator toincrease or decrease a magnitude of an operational characteristic of theat least one power regulator. The method may further comprise, causingthe at least one power regulator to maintain the magnitude of theoperational characteristic of the at least one power regulator. Thecausing the at least one power regulator may comprise, based on acorresponding increase function or a decrease function of the at leastone power regulator, increasing or decreasing the magnitude of theoperational characteristic of the at least one power regulator. Thepower production characteristic of the at least one power regulatorcomprises at least one of: a Maximum Power Point (MPP) of a power sourceof a plurality of power sources, a current versus voltage characteristicof the power source, the increase function, the decrease function, or anoperating temperature. The determining the power regulation signal maycomprises determining a change to an input of the central circuit basedon a determined operational characteristic of a power system associatedwith the plurality of power regulators and a plurality of power sources,and based on the determined change to the input of the central circuit,determining a change indication indicating a ratio of change or anamount of change in the magnitude of the operational characteristic ofthe at least one power regulator. The operational characteristic of theat least one power regulator may be at least one of an output voltage,an output current, an output power, an operating temperature, a dutycycle, an input voltage, an input current, an input power, a lifetime,or a frequency. The causing the at least one power regulator to controlmay be further based on a characteristic curve, wherein thecharacteristic curve may indicate a relationship between at least twooperational characteristics of the at least one power regulator of theplurality of power regulators, and wherein the characteristic curve maycomprise a droop over an operating range of the at least one powerregulator.

One or more aspects of the present disclosure may be embodied incomputer-usable data and computer-executable instructions, such as inone or more program modules, executed by one or more computers or otherdevices. Generally, program modules include routines, programs, objects,components, data structures, etc. that perform particular tasks orimplement particular abstract data types when executed by a processor ina computer or other device. The computer executable instructions may bestored on a computer readable medium such as a hard disk, optical disk,removable storage media, solid state memory, RAM, etc. As will beappreciated by one of skill in the art, the functionality of the programmodules may be combined or distributed as desired in variousembodiments. In addition, the functionality may be embodied in whole orin part in firmware or hardware equivalents such as integrated circuits,field programmable gate arrays (FPGA), or the like. Particular datastructures may be used to more effectively implement one or more aspectsof the disclosure, and such data structures may be within the scope ofcomputer executable instructions and computer-usable data describedherein.

Although the subject matter has been described in language specific tostructural features and/or methodological acts, it is to be understoodthat the subject matter defined in the appended claims is notnecessarily limited to the specific features or acts described above.Rather, the specific features and acts described above are disclosed asexample forms of implementing the claims.

1. A system comprising: a plurality of power sources configured togenerate power; and a plurality of power regulators, wherein each powerregulator of the plurality of power regulators comprises: a powerconverter configured to convert input power from a corresponding one ofthe plurality of power sources to output power; a regulator transceiverconfigured to receive at least one power regulation signal, wherein theat least one power regulation signal is associated with regulating anoperational characteristic of the power regulator, wherein the at leastone power regulation signal is one of a broadcast signal or a multicastsignal; and a regulator controller connected to the power converter andthe regulator transceiver, and configured to, based on the at least onepower regulation signal and based on a power production characteristicof the power regulator, control the power converter to increase ordecrease a magnitude of the operational characteristic of the powerregulator.
 2. The system of claim 1, further comprising a centralcircuit, wherein the central circuit comprises: a sensor configured tomeasure at least one of an input voltage, an input current, an outputvoltage, an output current, or an operating temperature of the centralcircuit; a central controller configured to: determine an operationalcharacteristic of the central circuit based on a measurement from thesensor, and determine the power regulation signal based on thedetermined operational characteristic of the central circuit; and acentral transceiver connected to the central controller, configured totransmit the power regulation signal to at least one power regulator ofthe plurality of power regulators.
 3. The system of claim 2, wherein theoperational characteristic of the central circuit is based on at leastone of: a difference or a ratio between a predetermined input voltageand a measured input voltage; a difference or a ratio between apredetermined input current and a measured input current; a differenceor a ratio between a predetermined input power and a measured inputpower; a difference or a ratio between a predetermined output voltageand a measured output voltage; a difference or a ratio between apredetermined output current and a measured output current; a differenceor a ratio between a predetermined output power and a measured outputpower; a difference or a ratio between a predetermined voltage gain anda measured voltage gain; a difference or a ratio between a predeterminedcurrent gain and a measured current gain; a difference or a ratiobetween a predetermined transresistance and a measured transresistance;or a difference or a ratio between a predetermined transconductance anda measured transconductance.
 4. The system of claim 1, wherein the powerregulation signal comprises a change indication.
 5. The system of claim4, wherein each power regulator of the plurality of power regulators isfurther configured to control its operational characteristic to increaseor decrease the magnitude of the operational characteristic of the powerregulator based on the change indication and a corresponding one of anincrease function, or a decrease function.
 6. The system of claim 5,wherein the power production characteristic of each power regulator ofthe plurality of power regulators comprises at least one of: a MaximumPower Point (MPP) of the corresponding one of the plurality of powersources; a current versus voltage characteristic of the correspondingpower source of the plurality of power sources; the increase function;the decrease function; or an operating temperature.
 7. The system ofclaim 2, wherein the central circuit comprises power busbars configuredto combine outputs of the plurality of power regulators.
 8. The systemof claim 1, wherein the power regulation signal is transmitted, from acentral circuit, as the broadcast signal or the multicast signal to eachpower regulator of the plurality of power regulators.
 9. The system ofclaim 1, wherein the operational characteristic of each power regulatorof the plurality of power regulators comprises at least one of an outputvoltage, an output current, an output power, an operating temperature, aduty cycle, an input voltage, an input current, an input power, alifetime, or a frequency.
 10. The system of claim 1, wherein each powerregulator of the plurality of power regulators further comprises asensor connected to the regulator controller, wherein the sensor isconfigured to measure at least one of an input voltage, an inputcurrent, an output voltage, an output current, or an operatingtemperature of the power regulator, and wherein the regulator controlleris further configured to control the power converter based on ameasurement from the sensor.
 11. The system of claim 1, wherein eachpower regulator of the plurality of power regulators stores acharacteristic curve defining a relationship between at least twooperational characteristics of the power regulator, wherein, thecharacteristic curve comprises a droop over an operating range of thepower regulator, and wherein the regulator controller is furtherconfigured to control the power converter to increase, decrease, ormaintain magnitudes of the operational characteristics of the powerregulator based on the characteristic curve.
 12. The system of claim 1,wherein the power converter, of each power regulator of the plurality ofpower regulators, is a direct current (DC) to direct current (DC-to-DC)converter or a DC to alternating current (DC-to-AC) converter comprisingat least a switching converter.
 13. The system of claim 1, wherein theplurality of power regulators, connected in series or in parallel, forma plurality of strings, wherein each of the plurality of stringscomprises a subset of the plurality of power regulators, and whereineach power regulator of the subset is configured to: connect, via inputterminals, to the corresponding one of the plurality of power sources;and provide, via output terminals, the output power.
 14. A methodcomprising: determining, by a central circuit, a power regulationsignal; transmitting, by a transceiver of the central circuit and to atleast one power regulator of a plurality of power regulators, the powerregulation signal as a broadcast signal or a multicast signal; and basedon the power regulation signal transmitted and based on a powerproduction characteristic of the at least one power regulator, causing,by the central circuit, the at least one power regulator to increase ordecrease a magnitude of an operational characteristic of the at leastone power regulator.
 15. The method of claim 14, further comprising,causing the at least one power regulator to maintain the magnitude ofthe operational characteristic of the at least one power regulator. 16.The method of claim 14, wherein the causing the at least one powerregulator comprises, based on a corresponding increase function or adecrease function of the at least one power regulator, increasing ordecreasing the magnitude of the operational characteristic of the atleast one power regulator.
 17. The method of claim 16, wherein the powerproduction characteristic of the at least one power regulator comprisesat least one of: a Maximum Power Point (MPP) of a power source of aplurality of power sources; a current versus voltage characteristic ofthe power source; the increase function; the decrease function; or anoperating temperature.
 18. The method of claim 14, wherein thedetermining the power regulation signal comprises: determining a changeto an input of the central circuit based on a determined operationalcharacteristic of a power system associated with the plurality of powerregulators and a plurality of power sources; and based on the determinedchange to the input of the central circuit, determining a changeindication indicating a ratio of change or an amount of change in themagnitude of the operational characteristic of the at least one powerregulator.
 19. The method of claim 14, wherein the operationalcharacteristic of the at least one power regulator is at least one of anoutput voltage, an output current, an output power, an operatingtemperature, a duty cycle, an input voltage, an input current, an inputpower, a lifetime, or a frequency.
 20. The method of claim 14, whereinthe causing the at least one power regulator to control is further basedon a characteristic curve, wherein the characteristic curve indicates arelationship between at least two operational characteristics of the atleast one power regulator of the plurality of power regulators, andwherein the characteristic curve comprises a droop over an operatingrange of the at least one power regulator.